General: Blue grama is a major warm season grass found throughout the Great Plains. It is found on the plains, prairies, and foothills of most western states. It is short (6 to 24 inches) stature and perennial with a prolific root system. This species has some phenotypic plasticity since in the southern states it grows normally as a bunch grass, but in the northern states and in the mountains, or in areas under heavy grazing pressure it is a sod former. Phenotypic plasticity is the ability of an organism to alter its physiology or morphology in response to changes in environmental conditions (Schlichting, 1986). Blue grama possesses the C-4 photosynthetic pathway for carbon fixation (Waller and Lewis, 1979).
Distribution: For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site. Blue grama is a major species of the western Great Plains and southwestern United States. It is also found growing in Mexico and the Canadian Provinces of Alberta, Saskatchewan and Manitoba.
Habitat: Blue grama is most effective when grown in the dryer parts of the northern and southern Great Plains and southwestern region of the U.S. It naturally grows in mixed stands, primarily with buffalograss (Bouteloua dactyloides), needle-and-thread ( Hesperostipa comata), western wheatgrass (Pascopyrum smithii), and green needlegrass (Nassella viridula)in a short grass prairie setting.
It will be associated with other species such as prairie sandreed and sand sagebrush in a sandier habitat.
Regularity: Regularly occurring
Regularity: Regularly occurring
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
BLM PHYSIOGRAPHIC REGIONS :
4 Sierra Mountains
5 Columbia Plateau
6 Upper Basin and Range
7 Lower Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
13 Rocky Mountain Piedmont
14 Great Plains
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
Occurrence in North America
Blue grama demonstrates good drought, fair salinity and moderate alkalinity tolerance. It grows well on soil types as varied as sandy to clayey in texture; however its growth is not as vigorous on true sands or clays. Blue grama is not tolerant of frequent flooding or submergence. It is also intolerant of shade and acidic soils. It is variably tolerant of fire and can be damaged if burned during active growth, especially under drought conditions. Blue grama grows at elevations of 3,500 feet up to 7,000 feet in New Mexico and has been reported growing at 10,000 feet. Forage production is best where annual precipitation is 12 to 14 inches and occurs during the warmest part of summer.
Blue grama is a densely tufted, native, perennial grass [47,55,112,118,131,160,164,167,171,365]. It may grow as a bunch grass [30,55,107,315] and form thick mats by tillering [118,167,171,184,208,365], frequently resulting in an open sod character [116,193,194,261,315]. Costello  contends that blue grama may assume a bunch grass form for a number of years, eventually assuming more of a turf character as the plant community becomes more closed. Others report that blue grama grows as a bunch grass in the south and is sod-forming in the north, at high elevations, and when closely grazed [316,355]. Radial advance of blue grama plants has been estimated at between 0.5 and 2 inches (1.3-5 cm) annually . Where it forms a dense cover, blue grama is an important soil-building grass . In the shortgrass prairie of the central and southern Great Plains, blue grama accounts for 75% to 90% of net primary production on most sites [101,109].
Blue grama patches may form ring patterns as blue grama develops a crown that is "pedastalled" on roots that extend 0.4 to 0.8 inch (1- 2 cm) above the soil. These roots are exposed to parasites and disease, resulting in loss of plant vigor and death of older plants at the center of patches .
Plant height at maturity ranges from 6 to 12 inches (15-30 cm) [131,193,240,274]. Blue grama leaves are flat and taper to a point , growing 1 to 10 inches (2.5-25 cm) long [7,47,188,261,349] and less than 1/8 inch (3 mm) wide [47,112,118,160,161,171,180,188,349], and persistent . Blue grama is solid-stemmed , and the flowering stems generally grow 7 to 18 inches (17-46 cm) tall [112,161,188,240,241,349]. Each inflorescence usually has 2 branches or spikes that extend at sharp angles from the main stem and are ascending to spreading and curved at maturity [47,124,188,349]. Blue grama has 20 to 90 spikelets per spike [112,164,180,241].
Blue grama fibrous root systems [30,107,274,356] are dense  and shallow [34,56,91,356]. Reports on rhizome formation are conflicting, with some authors reporting rhizome formation [116,137,164,167,180,265] and others disputing that information . Also unknown is whether or not stoloniferous ecotypes of blue grama exist as have been found in hairy grama, sideoats grama, and slender grama (Bouteloua repens) . White  found that in a greenhouse study, stolon development in blue grama is not controlled by day length, temperature, or shade except as they affect growth. Most blue grama plants in this study developed stolons if water, fertilizer, and light were adequate for sustained growth. Blue grama roots are usually less than 0.04 inches (1 mm) in diameter and often diminish to 0.008 inches (0.2 mm) with increasing depth . Roots of individual blue grama plants generally extend 12 to18 inches (30-46 cm) from the edge of the plant and 3 to 6 feet (0.9-1.8 m) deep [100,111,112,116,147,357]. Blue grama roots may penetrate deeper soil layers , and the maximum rooting depth of blue grama is approximately 6.5 feet (2 m) [82,110,116]. The density of blue grama root systems is attributed to abundance of branching; laterals are produced as frequently as 4.3 per inch (1.8 per cm) of main root in the upper 6 inches (15 cm) of soil. These laterals are up to 1 inch (2.5 cm) in length and branch to the 3rd order . The greatest branching of blue grama roots occurs in the top 18 inches (46 cm) of soil . Horizontal roots radiate in all directions from the base of blue grama stems, growing within 1.2 inches (3 cm) of the soil surface for up to 16 inches (40 cm). Lateral spreading of roots is more pronounced in mixed prairie vegetation than in the true prairie [112,356] and on more arid sites . Because the majority of blue grama roots are in the upper soil layers [100,111,235,358], it can respond rapidly to small amounts of rainfall [100,128]. In less xeric situations, the surface roots develop at a deeper level or follow an oblique course. Deeply penetrating roots usually descend obliquely or vertically from their origin .
The Flora of the Great Plains provides a morphological description and identification key for blue grama .
Catalog Number: US 81710
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): G. C. Nealley
Year Collected: 1887
Locality: Texas, United States, North America
- Holotype: Vasey, G. 1890. U.S.D.A. Div. Agrostol. Bull. 12 (1): 45.
Catalog Number: US 883201
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): J. G. Lemmon
Year Collected: 1882
Locality: Arizona, United States, North America
- Holotype: Dewey, L. H. 1894. Contr. U.S. Natl. Herb. 2: 531.
Catalog Number: US 865679A
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Card file verified by examination of alleged type specimen
Preparation: Pressed specimen
Collector(s): F. W. Humboldt & A. J. A. Bonpland
Locality: La Buffa do Guanaxuato. [La Bufa de Guanajuato?], Guanajuato, Mexico, North America
- Type fragment: Kunth, C. S. 1816. Nova Genera Sp. Pl. 1: 176.
Catalog Number: US 81708
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Preparation: Pressed specimen
Collector(s): C. G. Pringle
Year Collected: 1885
Locality: Chihuahua, Mexico, North America
- Holotype: Beal, W. J. 1896. Grasses N. Amer. 2: 416.
Habitat and Ecology
Elevation: The elevational range of blue grama in North America is 985 to 9,850 feet (300 to 3,000 m) [164,274]. The following table presents examples of elevation ranges for blue grama, broken down by state:
|Arizona||1,000 to 8,800 feet (305-2,700 m)||[17,35,49,145,173,193,194,215,228,267]|
|California||<7,550 feet (2,300 m)|||
|Colorado||3,500 to 10,500 feet (1,000-3,200 m)||[121,125]|
|Montana||2,400 6,100 feet (1,860 m)||[125,264]|
|New Mexico||4,500 to 8,500 feet (1,370-2,590 m)||[65,121,145,217,228,241]|
|Texas||1,500 to 1,900 feet (460-580 m)|||
|Utah||700 to 9,500 feet (213-2,900 m)||[125,274,365]|
|Wyoming||3,100 to 8,500 feet (950-2,600 m)|||
Climate: Blue grama generally requires 8 to 15 inches (203-381 mm) of annual precipitation , which occurs primarily in spring and summer months throughout its range [33,49,230,321]. The following table presents climate information for some of the areas in which blue grama occurs:
|Northern Great Plains||> 8 inches||-40 to 100 oF 120-160 frost-free days||[39,97,280]|
|mixed prairie||15 inches annually along northern and eastern boundaries, 9 inches along western and southern boundaries||January average: 1 to 23 oF |
July average: 68 oF
|shortgrass steppe||12 to 22 inches||150-200 frost-free days|||
|Southern Great Plains||18 to 34 inches||7 to 100 oF||[43,70,97]|
|Great Basin||irregular, < 7 inches||100-150 frost-free days|||
|Southwestern U.S.||17 inches||January minimum: 29 oF July maximum: 90 oF|||
Site types: Blue grama grows both in low-lying areas and on uplands [34,38,77,92,131,188,280,291]. It is found on dry prairies and sandhills in the northeastern United States and in Canada . In the western United States, blue grama is found east of the Continental Divide on valley floors, alluvial benches and fans, drainages, mesas, toeslopes, and steeper slopes up to 35% [35,38,47,49,50,93,153,180,215,241,264].
Soils: Blue grama occupies a range of well-drained [187,236,355] soil types, from fine to coarse textured [34,50,74,92,107,112,121,131,145,188,298,299,315,355]. It grows on clay [30,65,77,114,164], silt , fine loams [1,47], loams [15,280,316], sandy loams [65,77,118], sand [15,47,89,112,316], and gravelly soils [47,112,118,164]. Soil texture may affect reproductive development of blue grama; density of culms produced per plant, height of culms, density of viable seeds, and number of viable seeds decrease with decreasing soil coarseness . Finer soil textures may result in shallower penetration of moisture, greater water loss from runoff, and a consequent increase in abundance of blue grama on mixed-prairie sites in Canada . In a study of grassland in North Dakota, blue grama occurred more frequently on more xeric sites where infiltration of water is less efficient .
Tolerances: Blue grama is cold [355,359,365] and drought [16,34,71,74,87,94,261,266,274,315,365] tolerant. In laboratory tests, blue grama perennating structures (extravaginal crowns) survived 2 months of exposure of -31 degrees Fahrenheit (-35 oC) . Drought tolerance and adaptation to xeric conditions allow blue grama to occupy drier sites throughout its range [89,112,118,131,153,173,228,259,266,291,349]. Prolonged drought, however, results in decreased root numbers, spread, and depth of penetration in blue grama root systems . Blue grama has an opportunistic water use strategy, using water rapidly when available and becoming dormant under dry soil conditions [281,291]. Epstein and others  found that aboveground net primary production of blue grama generally increased in response to an increase in mean annual temperature, while production decreased in response to increasing mean annual precipitation. Blue grama production was highest with 8 to 12 inches (200-300 mm) of precipitation, and lowest at greater than 31 inches (800 mm) annual precipitation. In New Mexico, however, blue grama may be restricted to sites with higher soil moisture than adjacent areas [64,217]. Season of precipitation may be important to blue grama production; dry summers may cause tiller death and thinning of blue grama stands, while wet summers promote thickening of stands .
Blue grama is also tolerant of alkaline soils [188,315,316,334,349,355] and is rarely found on even weakly acid soils [315,334,355]. However, in a study in southeastern Arizona, blue grama was most abundant on acidic, relatively infertile, sandy clay loam soils . Blue grama has been reported as fair to moderately tolerant [172,315,334,355] and intolerant of salt, tending to have a shallow root system that avoids soil salinity [56,243]. Miyamoto  found that with applications of 50, 100, 150, and 200 milliequivalent (me)/liter of salt solution, blue grama germination began decreasing markedly at the highest concentration. Blue grama vegetative growth was also sensitive to salt solutions. In greenhouse experiments, Weiler  found that dry weight of blue grama was much lower when irrigated with saline solution than with tap water, and Weiler and Gould  found that heights of blue grama decreased with applications of increasing salt concentrations.
Key Plant Community Associations
Understory occurrence: Blue grama is a principal species in the aspen parklands of Canada, occurring
with rough fescue (Festuca altaica), porcupine grass (Hesperostipa spartea),
prairie Junegrass (Koeleria macrantha), slender wheatgrass (Elymus
trachycaulus), and mat muhly (Muhlenbergia richardsonis) [44,115]. Blue grama is also found in the understory of riparian cottonwood forests in the
Central Plains, commonly occurring with sand dropseed (Sporobolus cryptandrus) and
buffalo grass (Buchloe dactyloides) .
On the sagebrush steppe, blue grama occurs with big sagebrush
western wheatgrass (Pascopyrum smithii), threadleaf sedge (Carex
filifolia), prairie Junegrass, Sandberg bluegrass (Poa secunda), green needlegrass
(Nassella viridula), and needle-and-thread grass (Hesperostipa comata) [37,41]. In big sagebrush communities, blue grama occurs with big sagebrush,
gray horsebrush (Tetradymia canescens), and green rabbitbrush (Chrysothamnus
viscidiflorus). Common grass species in these communities
include crested wheatgrass (Agropyron cristatum), cheatgrass (Bromus tectorum),
prairie Junegrass, and bottlebrush squirreltail (Elymus elymoides) .
In salt-desert shrub communities, blue grama associated shrub species include
shadscale (Atriplex confertifolia), Gardner's saltbush (Atriplex
gardneri), mat saltbush (Atriplex corrugata), fourwing saltbush
(Atriplex canescens), black greasewood (Sarcobatus vermiculatus), winterfat
(Krascheninnikovia lanata), and spiny hopsage (Grayia spinosa). Associated
grass species include Indian ricegrass (Achnatherum hymenoides),
Sandberg bluegrass, galleta (Pleuraphis jamesii), alkali sacaton (Sporobolus
airoides), and sand dropseed [47,143].
In the evergreen oak woodlands of the southwest, blue grama occurs in the understory
with muhlys (Muhlenbergia spp.), plains lovegrass (Eragrostis intermedia), sideoats
grama (Bouteloua curtipendula), hairy grama (B. hirsuta), little bluestem
(Schizachyrium scoparium), and cane bluestem (Bothriochloa barbinodis)
In ponderosa pine (Pinus ponderosa) communities, blue grama occurs with
Colorado pinyon (P. edulis), Gambel oak (Quercus gambelii),
alligator juniper (Juniperus deppeana), common juniper (J. communis),
Saskatoon serviceberry (Amelanchier alnifolia), greenleaf manzanita (Arctostaphylos patula), black
sagebrush (A. nova), big sagebrush, Fendler's ceanothus (Ceanothus
curlleaf mountain-mahogany (Cercocarpus ledifolius), true
montanus), snowberry (Symphoricarpos spp.), ninebark (Physocarpus
spp.), and antelope bitterbrush (Purshia tridentata)
[13,57,96,121,145]. Associated grass species
include pinegrass (Calamagrostis rubescens), elk sedge (Carex geyeri), Idaho
fescue (Festuca idahoensis), bluebunch
wheatgrass (Pseudoroegneria spicata), purple threeawn (Aristida
purpurea), prairie Junegrass, galleta, mountain muhly (Muhlenbergia
montana), Kentucky bluegrass (Poa pratensis), mutton grass (Poa
fendleriana), needle-and-thread grass, and bottlebrush squirreltail [13,13,28,35,57,96,118,121,228].
In pinyon-juniper communities, blue grama commonly occurs with Colorado
pinyon, singleleaf pinyon (P. monophylla), alligator juniper, Utah
juniper (J. osteosperma), oneseed juniper (J. monosperma), Gambel oak,
Saskatoon serviceberry, black sagebrush, big sagebrush, fourwing saltbush,
true mountain-mahogany, Stansbury cliffrose (Purshia mexicana var. stansburiana),
green rabbitbrush, antelope bitterbrush, green ephedra (Ephedra
viridis), red barberry (Mahonia haematocarpa), broom
snakeweed (Gutierrezia sarothrae), and turpentine bush (Ericameria laricifolia). Associated grass species include
western wheatgrass, poverty threeawn (Aristida divaricata),
sideoats grama, black grama (B. eriopoda), prairie Junegrass, crested
wheatgrass, muhlys, dropseeds (Sporobolus spp.),
galleta, mutton grass, cheatgrass, fringed brome (Bromus ciliatus),
California brome (B. carinatus), bottlebrush squirreltail,
Indian ricegrass, needle-and-thread grass, New Mexico feathergrass (Hesperostipa neomexicana),
Sandberg bluegrass, and
purple threeawn [29,46,67,78,118,120,182,228,330].
Grassland associations: Blue grama is an important component of the shortgrass prairie [22,33,91,118,184],
co-dominating with buffalo grass and occurring with hairy grama, purple threeawn,
Sandberg bluegrass, threadleaf sedge, and
little bluestem [3,7,22,33,91,94,230].
In the central and northern Great Plains mixed
prairies, blue grama occurs with prairie
sandreed (Calamovilfa longifolia),
western wheatgrass, bluebunch wheatgrass, buffalograss, prairie Junegrass, needle-and-thread grass, hairy grama, green needlegrass,
Sandberg bluegrass, and needleleaf sedge (Carex duriuscula) [1,2,3,10,31,33,112,264]. Shrubs
occurring in these systems include fringed sagebrush (Artemisia frigida), big sagebrush,
rubber rabbitbrush (C. nauseosus), and plains prickly-pear (Opuntia
In the southern Great Plains, blue grama occurs with curly mesquite (Hilaria
belangeri), galleta, New Mexico feathergrass, sideoats grama, tobosa (Pleuraphis mutica), vine-mesquite
(Panicum obtusum), purple threeawn, Indian ricegrass, prairie Junegrass,
buffalograss, plains lovegrass, and Texas tussockgrass (Nasella
leucotrica) [63,69,144]. Woody plants
occurring in these communities include honey mesquite (Prosopis glandulosa)
and lotebush (Ziziphus obtusifolia) .
In the semi-desert grasslands of the Southwest, blue grama occurs with hairy grama, sideoats grama, black grama, bush muhly
(Muhlenbergia porteri), threeawn (Aristida spp.), buffalograss, plains lovegrass, little
bluestem, sand dropseed, bottlebrush squirreltail, curly mesquite,
galleta, western wheatgrass, Indian ricegrass, New Mexico feathergrass, and needle-and-thread grass [17,70,122,146,270].
Shrubs occurring in these communities include shrub live oak (Quercus
(Cercocarpos spp.), skunkbush sumac (Rhus trilobata), and desert ceanothus
(Ceanothus greggii) .
Classifications describing plant communities in which blue grama occurs as a
dominant species are as follows:
New Mexico [12,13,13,121,145,148,149,182,217,228,257,337]
North Dakota [239,251,376]
In forest communities, blue grama occurs as a
co-dominant with ponderosa pine [12,13,35,121,145,148,173,228,267,337],
oneseed juniper , alligator juniper [35,182,217,337], Utah juniper
[35,228], oneseed juniper [149,228,337], singleleaf pinyon [35,337], and Colorado
In shrub communities, blue grama occurs as a
co-dominant with sand sagebrush (Artemisia filifolia) , fourwing
saltbush , rubber rabbitbrush , Parry's rabbitbrush (Ericameria parryi)
, winterfat , and big sagebrush [148,149,183,341].
grassland communities, blue grama occurs as a co-dominant with buffalo grass
[233,340], needle-and-thread grass [227,233,239,264,382], prairie Junegrass
, little bluestem, plains muhly (Muhlenbergia cuspidata)
, bluebunch wheatgrass , western wheatgrass [149,149,183,239],
alkali sacaton , saltgrass (Distichlis spicata) , galleta
, Kentucky bluegrass , threadleaf sedge [233,239], and sun
Habitat: Rangeland Cover Types
This species is known to occur in association with the following Rangeland Cover Types (as classified by the Society for Range Management, SRM):
More info for the terms: cover, shrub, vine
SRM (RANGELAND) COVER TYPES :
101 Bluebunch wheatgrass
102 Idaho fescue
104 Antelope bitterbrush-bluebunch wheatgrass
105 Antelope bitterbrush-Idaho fescue
107 Western juniper/big sagebrush/bluebunch wheatgrass
109 Ponderosa pine shrubland
110 Ponderosa pine-grassland
206 Chamise chaparral
209 Montane shrubland
211 Creosote bush scrub
215 Valley grassland
301 Bluebunch wheatgrass-blue grama
302 Bluebunch wheatgrass-Sandberg bluegrass
303 Bluebunch wheatgrass-western wheatgrass
304 Idaho fescue-bluebunch wheatgrass
306 Idaho fescue-slender wheatgrass
307 Idaho fescue-threadleaf sedge
309 Idaho fescue-western wheatgrass
310 needle-and-thread grass-blue grama
311 Rough fescue-bluebunch wheatgrass
312 Rough fescue-Idaho fescue
314 Big sagebrush-bluebunch wheatgrass
315 Big sagebrush-Idaho fescue
316 Big sagebrush-rough fescue
317 Bitterbrush-bluebunch wheatgrass
320 Black sagebrush-bluebunch wheatgrass
321 Black sagebrush-Idaho fescue
322 Curlleaf mountain-mahogany-bluebunch wheatgrass
323 Shrubby cinquefoil-rough fescue
324 Threetip sagebrush-Idaho fescue
401 Basin big sagebrush
402 Mountain big sagebrush
403 Wyoming big sagebrush
404 Threetip sagebrush
405 Black sagebrush
406 Low sagebrush
408 Other sagebrush types
411 Aspen woodland
412 Juniper-pinyon woodland
413 Gambel oak
414 Salt desert shrub
415 Curlleaf mountain-mahogany
416 True mountain-mahogany
417 Littleleaf mountain-mahogany
503 Arizona chaparral
504 Juniper-pinyon pine woodland
505 Grama-tobosa shrub
509 Transition between oak-juniper woodland and mahogany-oak association
601 Bluestem prairie
602 Bluestem-prairie sandreed
603 Prairie sandreed-needlegrass
604 Bluestem-grama prairie
605 Sandsage prairie
611 Blue grama-buffalo grass
613 Fescue grassland
614 Crested wheatgrass
701 Alkali sacaton-tobosagrass
702 Black grama-alkali sacaton
703 Black grama-sideoats grama
704 Blue grama-western wheatgrass
705 Blue grama-galleta
706 Blue grama-sideoats grama
707 Blue grama-sideoats grama-black grama
710 Bluestem prairie
712 Galleta-alkali sacaton
715 Grama-buffalo grass
717 Little bluestem-Indiangrass-Texas wintergrass
719 Mesquite-liveoak-seacoast bluestem
720 Sand bluestem-little bluestem (dunes)
721 Sand bluestem-little bluestem (plains)
722 Sand sagebrush-mixed prairie
724 Sideoats grama-New Mexico feathergrass-winterfat
725 Vine mesquite-alkali sacaton
727 Mesquite-buffalo grass
730 Sand shinnery oak
731 Cross timbers-Oklahoma
732 Cross timbers-Texas (little bluestem-post oak)
735 Sideoats grama-sumac-juniper
802 Missouri prairie
803 Missouri glades
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
More info for the term: cover
SAF COVER TYPES :
40 Post oak-blackjack oak
46 Eastern redcedar
66 Ashe juniper-redberry (Pinchot) juniper
67 Mohrs (shin) oak
219 Limber pine
220 Rocky Mountain juniper
237 Interior ponderosa pine
238 Western juniper
240 Arizona cypress
241 Western live oak
247 Jeffrey pine
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
More info for the term: shrub
KUCHLER  PLANT ASSOCIATIONS:
K010 Ponderosa shrub forest
K011 Western ponderosa forest
K016 Eastern ponderosa forest
K017 Black Hills pine forest
K019 Arizona pine forest
K020 Spruce-fir-Douglas-fir forest
K022 Great Basin pine forest
K023 Juniper-pinyon woodland
K024 Juniper steppe woodland
K027 Mesquite bosques
K031 Oak-juniper woodland
K032 Transition between K031 and K037
K037 Mountain-mahogany-oak scrub
K038 Great Basin sagebrush
K044 Creosote bush-tarbush
K045 Ceniza shrub
K053 Grama-galleta steppe
K054 Grama-tobosa prairie
K055 Sagebrush steppe
K056 Wheatgrass-needlegrass shrubsteppe
K057 Galleta-threeawn shrubsteppe
K058 Grama-tobosa shrubsteppe
K059 Trans-Pecos shrub savanna
K060 Mesquite savanna
K061 Mesquite-acacia savanna
K062 Mesquite-live oak savanna
K063 Foothills prairie
K065 Grama-buffalo grass
K068 Wheatgrass-grama-buffalo grass
K069 Bluestem-grama prairie
K070 Sandsage-bluestem prairie
K074 Bluestem prairie
K075 Nebraska Sandhills prairie
K076 Blackland prairie
K081 Oak savanna
K083 Cedar glades
K084 Cross Timbers
K085 Mesquite-buffalo grass
K086 Juniper-oak savanna
K087 Mesquite-oak savanna
K088 Fayette prairie
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES10 White-red-jack pine
FRES21 Ponderosa pine
FRES28 Western hardwoods
FRES30 Desert shrub
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES36 Mountain grasslands
FRES38 Plains grasslands
FRES40 Desert grasslands
FRES42 Annual grasslands
Habitat & Distribution
Proper seedbed preparation is always necessary when trying to establish any native grass or wildflower species. For the best results seed of blue grama should be drilled on a firm and weed free seed bed with a depth band and packer wheel equipped native grass drill. Depth of seeding should be ¼ to ½ inch. Broadcasting the seed is an alternative planting option. However, the seed should then be incorporated to provide seed to soil contact or at least pressed into the soil with a cultipacker. Seeding rate varies depending on the planting site and method. Drill planted seeding rates are 25 to 40 pure live seeds (PLS) per square foot or 1 to 3 pounds PLS per acre. The seeding rate should be increased by 50 to 100 percent for broadcasting, harsh sites, south and west exposures, and where early or dense cover is required.
Blue grama cultivars have a large number of seeds per pound somewhere between 700,000 and 800,000 seeds/pound. Suitable planting dates are April to mid-May in the central Great Plains, slightly earlier in the southern Great Plains and June 15 to July 15 in the southwestern U.S. Wilson et al. (1976) found that blue grama seedlings avoid drought in three ways: 1) by increasing water uptake, 2) by adjusting leaf area, and 3) by reducing transpiration. The relative importance of each depends on the morphological stages of the seedling development and severity of drought conditions.
Briske and Wilson (1980) studied the extent and timing of adventitious (permanent) root development in blue grama seedlings. They discovered that if blue grama seedlings did not initiate and develop adventitious roots within 6 to 10 weeks after emergence they often died. Seedling death was caused by the expansion of leaf area beyond the ability of the seedlings seminal roots to provide adequate moisture. Without adventitious root development an increased transpiration stress was causing seedling and stand mortality. To develop adventitious roots the seedlings require a period during which the soil surface will continuously remain moist for 2 to 4 days. This moisture requirement is caused by the growth form of blue grama seedlings (Hyder et.al., 1971) that elevates the point of adventitious root growth to a point very near the soil surface. Weaver and Zink (1945) reported that blue grama seedlings grown without adventitious roots died after 8 weeks. Weaver (1926) explained that the root structure of established blue grama plants are exceedingly fine and spread widely in the surface soil, often to distances of 12 to 18 inches.
Based on studies in:
USA: California, Cabrillo Point (Grassland)
This list may not be complete but is based on published studies.
- L. D. Harris and L. Paur, A quantitative food web analysis of a shortgrass community, Technical Report No. 154, Grassland Biome. U.S. International Biological Program (1972), from p. 17.
Fire Management Considerations
With normal precipitation, blue grama is not harmed by prescribed burning, but may decrease following burning for 2 to 3 years during drought years . On a semidesert grassland site in Arizona, blue grama declined significantly (p<0.001) during the 1st season following a prescribed burn; however, it recovered fully after 2 postfire years . This study was part of an extensive of body of research on fire effects in semidesert grassland, oak savanna, and Madrean oak woodlands of southeastern Arizona. See the Research Project Summary of this work for more information on burning conditions, fires, and fire effects on more than 100 species of plants, birds, small mammals, and grasshoppers.
Annual burning may favor blue grama. On aspen-parkland sites in central Alberta, blue grama occurred in at least 10% of the plots that had been repeatedly burned but did not occur in adjacent, unburned sites . Gibson and Towne  also found that blue grama occurred on sites that had been annually burned for several years in a Kansas tallgrass prairie, but it did not occur on adjacent unburned sites. In a study at the Konza Prairie Research Natural Area in Kansas, average cover of blue grama was comparatively higher on annually burned sites than on sites burned once every 4 years or unburned sites . On paired plots in North Dakota, however, blue grama frequency varied little between burned and unburned sites.
Season of burning: Blue grama may respond differently based on the season of prescribed fire activities. Spring burning in the shortgrass prairie may result in a greater reduction in blue grama production than fall burning, though recovery usually occurs within 3 growing seasons. Height reductions in blue grama can also be expected during the initial growing season, with recovery likely after the 2nd growing season . In the mixed prairie, blue grama may be favored by early and mid-spring burning [181,218,222]. On a site in the northern mixed prairie of Saskatchewan, blue grama growth increased following a late spring prescribed burn . In the mixed prairie of North Dakota, both spring (May) and fall (October) fires increased blue grama production with spring burning resulting in the greater increase . In a Kansas study, blue grama was least abundant on unburned sites and most abundant on early spring-burned sites. On one site in particular, the unburned pasture averaged 4.5% plant composition blue grama, late-spring burning averaged 31%, mid-spring burning 40%, and early-spring burning 47% blue grama . In the 1st and 2nd growing seasons following a spring burn in Nebraska mixed prairie, blue grama experienced a significant increase (p<0.10) in basal cover on burned plots compared to unburned plots . On sites in South Dakota, blue grama increased from 4 to 11% cover in the 1st growing season following a spring prescribed burn and increased from 12 to 18% cover during the 2nd growing season . Following early spring prescribed burning in Texas, blue grama yield increased up to 400 pounds per acre (452 kg/ha) in the 1st growing season . In a Montana study, prescribed burning resulted in increased yields over unburned areas, though initial late spring growth was greater on unburned plots . Spring burning (April) of blue grama stimulated production by mid- or late June, while fall burning (October) stimulated production to a lesser degree [374,375].
In the Alberta blue grama steppe, however, dry matter production was reduced 50% (from prefire production) during the 1st season following a spring fire and reduced 15% during the 2nd season, with recovery complete the 3rd season. Fall burning resulted in a 30% decrease in production, with recovery complete by the 2nd postburn season . Whisenant and Uresk  also found that prescribed burning in April reduced blue grama growth during the initial growing season. In studies in South Dakota, spring (April) burning was found to reduce productivity of blue grama whereas response to fall (October) burning was variable; increasing production when precipitation was adequate and decreasing it when precipitation was low. Late June prescribed burning in New Mexico inhibited blue grama growth throughout the growing season, though at the end of the season in October, blue grama on control sites was not significantly greater in height than on burned sites. Blue grama biomass was also not significantly different between burn and control plots, demonstrating that blue grama can recover from burning during the course of the growing season relative to controls .
Plant response to prescribed fire: During the 1st growing season following a fall fire in Nebraska, blue grama on the burned site initially had greater phytomass than blue grama on the control site. By the end of the growing season, however, the unburned site had relatively greater phytomass than the burned site . Trlica  found that the root crown circumference of blue grama increased 10 to 15% following spring, summer, and fall prescribed fire treatments, with similar increases occurring in control treatments also. Seedstalk production of blue grama in this study experienced greater increases following the fall burns than the spring and summer burns, though all burn treatments resulted in greater seedstalk production than the control. According to Pieper and others , season of burning had no significant effect (p<0.05) on height of blue grama plants, nor did plant heights differ between burned and unburned plots. Burning combined with nitrogen fertilizer, however, significantly increased (p<0.05) blue grama seedstalk heights and densities over those on the control and burned-only plots. There was no significant difference in seedstalk height and density between burned and unburned plots.
Other management considerations: A 3- to 4-month rest from grazing is recommended after fire .
Broad-scale Impacts of Plant Response to Fire
Fire exclusion, and subsequent woody plant invasion, has resulted in blue grama
decline. Combined effects of fire exclusion, agriculture, and other development
has reduced blue grama populations by 48% (based upon herbarium records) in the
Plant Response to Fire
Fire favors blue grama, generally increasing its occurrence, production, and percent cover [20,29,135,136,246,323,324,367]. Blue grama frequency may increase but productivity may decrease for a few years following fire . Blue grama has on-site surviving rhizomes that may be stimulated by fire [57,255]. Response of blue grama to fire may be dependant on precipitation following the fire; "wet" years tend to increase blue grama yield . Blue grama seed  and seedstalk production may also be stimulated by fire .
Immediate Effect of Fire
POSTFIRE REGENERATION STRATEGY :
Secondary colonizer (on-site or off-site seed sources)
In grassland ecosystems, fires may occur in any year, provided the grass is cured and ready to burn. In the plains grasslands, mean fire intervals likely range from 4 to 20 years depending on climates and ignition sources. Fire in grasslands can burn over large areas until a break in terrain or a change in weather stops the fire . In desert grasslands where blue grama may dominate, reductions in fire frequency result in shrub invasion and substantially less grass cover . Fire occurring during periods of drought combined with wind erosion may retard the process of succession .
Grassland fuels, generally fine fuels, burn readily. However, compact arrangement of stems in the "tufts" of bunchgrasses makes this portion of the plant difficult to ignite. Once ignited, they can smolder for long periods of time if enough material has accumulated. Plant density is a critical factor in a grassland's ability to propagate fire. Heat output is relatively low, so fairly continuous fuels are necessary for fire to spread .
FIRE REGIMES for plant communities and ecosystems in which blue grama occurs are summarized below. For further information regarding FIRE REGIMES and fire ecology of communities and ecosystems where blue grama is found, see the 'Fire Ecology and Adaptations' section of the FEIS species summary for the plant community or ecosystem dominants listed below.
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|Nebraska sandhills prairie||Andropogon gerardii var. paucipilus-Schizachyrium scoparium|
|bluestem-Sacahuista prairie||Andropogon littoralis-Spartina spartinae|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||Artemisia tridentata var. tridentata||12-43 |
|mountain big sagebrush||Artemisia tridentata var. vaseyana||15-40 [26,75,253]|
|Wyoming big sagebrush||Artemisia tridentata var. wyomingensis||10-70 (40**) [354,383]|
|saltbush-greasewood||Atriplex confertifolia-Sarcobatus vermiculatus|
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||5-100|
|plains grasslands||Bouteloua spp.|
|blue grama-needle-and-thread grass-western wheatgrass||Bouteloua gracilis-Hesperostipa comata-Pascopyrum smithii|
|blue grama-buffalo grass||Bouteloua gracilis-Buchloe dactyloides|
|grama-galleta steppe||Bouteloua gracilis-Pleuraphis jamesii|
|blue grama-tobosa prairie||Bouteloua gracilis-Pleuraphis mutica||275]|
|curlleaf mountain-mahogany*||Cercocarpus ledifolius||13-1000 [27,312]|
|mountain-mahogany-Gambel oak scrub||Cercocarpus ledifolius-Quercus gambelii|
|juniper-oak savanna||Juniperus ashei-Quercus virginiana|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||Juniperus scopulorum|
|Ceniza shrub||Larrea tridentata-Leucophyllum frutescens-Prosopis glandulosa|
|wheatgrass plains grasslands||Pascopyrum smithii|
|Mexican pinyon||Pinus cembroides||20-70 [258,339]|
|Colorado pinyon||Pinus edulis||10-49 |
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [25,32,234]|
|galleta-threeawn shrubsteppe||Pleuraphis jamesii-Aristida purpurea||275]|
|quaking aspen (west of the Great Plains)||Populus tremuloides||7-120 [25,170,249]|
|mesquite-buffalo grass||Prosopis glandulosa-Buchloe dactyloides|
|Texas savanna||Prosopis glandulosa var. glandulosa||275]|
|mountain grasslands||Pseudoroegneria spicata||3-40 (10**) [24,25]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.|
|blackland prairie||Schizachyrium scoparium-Nassella leucotricha|
|Fayette prairie||Schizachyrium scoparium-Buchloe dactyloides|
|little bluestem-grama prairie||Schizachyrium scoparium-Bouteloua spp.||275]|
More info for the terms: climax, competition, cover, litter, tiller, tree
Blue grama is primarily a late seral to climax grass species [44,103,110,114,140,173,212,283,298,299,304,343], though it may appear infrequently in early seral vegetation as isolated clumps . When it occurs as an understory species, blue grama is found primarily in open forests [190,191,344]. Pieper  found that blue grama biomass increased substantially with reductions in pinyon-juniper canopy cover. Though not tolerant of shade [207,277,315,334,355], blue grama is not affected as much by canopy cover as it is by accumulations of tree litter, which may reduce blue grama production . Root competition from trees in forested areas may also reduce the growth of blue grama . In the tall grass prairie, blue grama forms a late-seral short grass stage with buffalo grass; these two species make up approximately half the cover during this seral stage .
Following disturbance, recolonization of blue grama is a relatively slow process that differs depending on the spatial extent of the disturbed patch. Disturbances smaller than an individual plant reduce blue grama cover by killing tillers, and recolonization is primarily by tiller replacement from the damaged plant. As patch size increases and entire blue grama plants are killed, recolonization is through seedling establishment. As a result, these larger disturbances not only reduce cover but also kill individual plants . However, distance from a disturbed patch to areas bordering the disturbed area may have a greater effect than size of the disturbance on recovery time of blue grama . Coffin and others  found that blue grama is likely to recolonize agricultural fields (large disturbances) in shortgrass prairie systems within 50 years of abandonment, while also subject to grazing. Establishment of blue grama may be slowed on continuously disturbed areas because fewer pre-existing plants may survive over long periods of disturbance . Recovery of blue grama on disturbed sites may be constrained by soil texture, climatic factors, and seed production and availability [102,103], as well as by type and intensity of disturbance . Recovery of blue grama is greatly favored by increased moisture content and deeper soils .
Breeding system: No information
Pollination: No information
Seed production: Seed production of blue grama is generally low, but may be plentiful in favorable years [112,198,316]. Seed yields of 100 to 180 pounds per acre (112 kg/ha) have been obtained from natural stands . Amount of seed produced by blue grama depends on whether moisture is plentiful and temperatures are cool during the period of blossoming and seed formation [138,349]. Seed production may also be reduced by shading . In years of good growing conditions, blue grama may produce 2 or 3 seed crops . Presence of seed heads and seed head densities of blue grama may be increased by repeated annual burning [18,19].
Seed dispersal: Blue grama seed is dispersed by wind , insects , ingestion by large herbivores [272,282], and by adhesion to animal hides, fur, and feathers [231,329]. Wind disperses seed a few meters. In a seed dispersal study in Pennsylvania, Laughlin  found best seed dispersal occurred when blue grama fruits adhered to elk and bison fur. Since both ungulates are extirpated from large portions of their former range, long-distance seed dispersal of blue grama may be adversely affected. Fragmented populations are "trapped," with few opportunities for seed dispersal and population exchanges of genetic traits.
Seed banking: No information
Germination: In the tall grass prairie of Kansas and Nebraska, Blake  found that blue grama germination rates ranged between 3 and 31% over a 4-year period. In laboratory experiments, the highest rates of blue grama germination were achieved at day/night temperatures of 85/64.5 degrees Fahrenheit (29.5/18 oC), compared to 2 other treatments at 55.5/44.5 degrees Fahrenheit (13/7 oC) and 75/55.5 degrees Fahrenheit (24/13 oC), respectively. Jordan and Haferkamp  found the minimum germination temperature of blue grama to be approximately 51 degrees Fahrenheit (10.6 oC), while Knipe  achieved 94% germination at constant temperatures ranging from 60 to 100 degrees Fahrenheit (140-212 oC). Increases in the level of water stress generally cause a delay in the initiation and a decline in the rate of germination [52,221].
Seedling establishment/growth: Blue grama seedling establishment, survival, and growth are highest when isolated from neighboring adult plants. Adult blue grama plants effectively exploit water stored in the soil zone used by blue grama seedlings, increasing competition and decreasing seedling emergence and root development . Competition with other grasses may also reduce survival  and development  of blue grama seedlings. In field experiments at the Central Plains Experimental Range in northeast Colorado, Aguilera and Lauenroth  found the emergence of seedlings 20 days after seeding was 1 order of magnitude higher without neighboring adult plants than with neighbors (p<0.0001). Seedlings growing without the presence of active roots from neighboring adults had more leaves (p<0.0001) and were taller (p<0.0001) than seedlings growing with active roots present. At the end of the growing season, seedlings with neighbors excluded had more tillers and adventitious roots than seedlings with neighbors present (p<0.0001). A 2nd study further supports these conclusions, finding that establishment of blue grama seedlings was promoted by gap disturbances that involved removal of established adult blue grama plants . Increased opening size may also affect blue grama seedlings, resulting in higher emergence and greater survival rates . Blue grama seedlings develop rapidly; they may tiller when only 21 days old and flower at 2 months .
Consistent blue grama establishment requires average soil temperatures above 59 degrees Fahrenheit (15 oC), 2 properly spaced 2- to 4-day periods with a continuously moist soil surface (1 for emergence and 1 for adventitious root development), and a soil water potential of -0.3 bars in the 0 to 15 inch (0-40 cm) zone at the time of emergence . Blue grama seedlings have a single seminal root that is short-lived; therefore, seedling establishment requires development and extension of adventitious roots [66,268,355]. Ries and Svejcar  found that development of adventitious roots in the northern Great Plains occurred approximately 14 days after blue grama seedling emergence. Light is an important factor in the formation of adventitious roots. In laboratory experiments, blue grama seedlings only formed adventitious roots at the soil surface . Under usual range conditions, the development of adventitious roots is initiated in dry soil and seedling mortality may result [296,297].
Growth Form (according to Raunkiær Life-form classification)
Life History and Behavior
More info for the term: severity
Blue grama is a warm season grass species [28,47,55,107,131]. Growth of blue grama begins late in the season [94,112,349], depending on soil temperature  and how much moisture is available [188,349]. In 1 study in the Northern Great Plains, blue grama growth did not begin until soil temperatures at 6-inch (15.2 cm) depths averaged 52 degrees Fahrenheit (11 oC) . Growth may cease during long droughts, but begins again upon return of favorable moisture and temperature conditions [7,94,113,118,161,177,188,207,261,349,365]. In a field study in northern Colorado, blue grama demonstrated a rapid response to a simulated 0.2-inch (5 mm) rainfall event following a period of water stress . The severity of the drought, however, may determine the ability of blue grama to recover. New blue grama root growth in response to increased moisture availability depends on duration of the soil water increase. Blue grama responds to a small rainfall event following a period of drought by increasing the water uptake of surviving roots. However, after a large rainfall event, water absorption is the result of uptake by both surviving and new roots . Blue grama can effectively mobilize, utilize, and replenish total nonstructural carbohydrates during short periods of favorable growing conditions, contributing to both its drought tolerance and rapid regrowth capability .
Growth of blue grama generally begins from mid-April [161,240] to June [315,319] and continues into October , reaching maturation in 2 months [76,112,240,261,315]. Tillering occurs in early June in the central Great Plains . Greatest increases in blue grama leaf area generally occur in June , and maximum leaf heights may be reached as early as mid-June  or late July . Blue grama flowers from July to August, with seeds ripening and dispersing from August to October [123,240].
Flowering of blue grama is dependent on geographic distribution, occurring earlier to later along both north/south and west/east gradients . In the northern Great Plains, blue grama flowering occurs primarily in July [81,112,161]; in the central Great Plains, flowering occurs from July through August [123,319]. In Montana, blue grama is finished flowering by mid-July . Blue grama flowers from July to October in New Mexico , Arizona  and Texas . Flowering of blue grama is also directly impacted by immediate moisture availability, and later flowering of a population may be due to later availability of moisture . Blue grama seeds usually mature in late summer [137,188,316,349] or fall [30,107,112], and seed heads ripen rapidly as they near maturity . Senescence occurs in late October or early November . Approximately 12% of overwintering blue grama shoots become reproductive .
Molecular Biology and Genetics
Barcode data: Bouteloua gracilis
Statistics of barcoding coverage: Bouteloua gracilis
Public Records: 3
Specimens with Barcodes: 5
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N4 - Apparently Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: Bouteloua gracilis occurs throughout southwestern Canada, throughout the southwestern and central United States into western Mexico, rarely into the eastern United States (Welsh, 1993).
In Missouri, blue grama is ranked "critically imperiled" due to extreme rarity or vulnerability to extirpation from the state .
Please consult the PLANTS Web site and your State Department of Natural Resources for this plant’s current status (e.g. threatened or endangered species, state noxious status, and wetland indicator values).
Pests and potential problems
Grasshoppers damage blue grama stands and consume forage. The white grub larvae of the common green June beetle (Cotia nitida) feed on roots and can cause stand loss. Mankin (1969) detailed several leaf and tar spot and rust diseases common on blue grama found in South Dakota.
Harlan et al. (1956) warned of thrip and gall midge infestations occurring in blue grama seed production fields.
Blue grama production may increase following overstory-removal treatments in
pinyon-juniper communities [95,97]. Clary and Jameson  found that blue grama production increased from 31 kg/ha pretreatment to
350 kg/ha posttreatment.
Blue grama may substantially retard growth of tree seedlings, reducing their
size, branching, and vigor .
Blue grama provides year-long grazing, but rotational grazing is recommended
to promote vigor and herbage production [274,347]. Blue
grama cover and net primary productivity are higher under short-duration grazing
strategies than continuous grazing strategies . Blue grama is generally tolerant of grazing
[49,144,336,365], increasing under
grazing pressure [20,43,44,62,87,187,209,219,225,293,318,322,328,345] and resisting trampling
[219,238,336]. Blue grama withstands clipping or grazing more effectively when grazed
after it has matured or when it is only slightly grazed during its growing
period [261,347]. Blue grama possesses primarily
culmless vegetative shoots in which the actively growing tissue is not elevated
to within reach of grazing animals, so potential for rapid regrowth is
preserved [21,62]. In one study, blue grama plants on
grazed sites allocated a higher percentage of biomass and nitrogen to the roots,
while those plants on ungrazed areas allocated a higher percentage to
aboveground production, demonstrating a potential strategy for responding to
grazing impacts .
Blue grama is often more prevalent on areas
subject to grazing than on areas where grazing has been excluded [204,206,227,288,309,320,326]. Sims and others
 found that blue grama
production increased more in response to heavy grazing treatments than to light,
moderate or control treatments. In North Dakota, relative basal cover of blue grama
was significantly lower (p<0.05) on sites protected from grazing than on
sites subject to grazing treatments . In a mixed grass
community in southwestern North Dakota, cover of blue grama was lower in
exclosures than in the adjacent grazed areas . The relative basal cover (%) of blue grama
on grazed and ungrazed sites was as follows :
However, there was little difference herbage production on grazed versus ungrazed sites,
due to significantly (p<0.0041) increased height of blue grama on the
ungrazed site . On pinyon-juniper sites in Arizona over a 13-year
period, blue grama decreased on grazed sites, though a greater decrease was
observed with the exclusion of grazing . At the Central
Plains Experiment Station, a study conducted over 2 years found that blue grama
basal cover was greater on "heavily grazed" than on "lightly
grazed" sites . In contrast, Smith  found that blue grama
increased 8-fold on lightly grazed sites, 4-fold under moderate grazing, and
only 1.25-fold under heavy grazing in Colorado.
Blue grama may decrease if subject to
continued heavy grazing [20,94,205], especially when accompanied by dry conditions
grazing also encourages a sod-forming rather than bunchgrass growth habit in
blue grama [179,193,194,208]. Heavy grazing can potentially
reduce tillering and tiller weight, and decrease concentrations of total
nonstructural carbohydrates in blue grama forage [292,305].
Large increases in the basal cover of blue grama in the mixed prairie
combined with decreases in the cover of other species, like needle-and-thread
indicate deterioration of range conditions [264,328].
Buwai and Trlica  found
that repeated defoliation treatments reduced herbage yield and vigor of blue
grama plants below that of undefoliated control plants. In general, basal
cover (%) was less for heavily defoliated plants than for moderately defoliated
plants, and all heavily defoliated plants had at least a 50% reduction in basal
cover as compared with the undefoliated plants. Defoliation
also reduced plant heights 40 to 80% below that of undefoliated control
plants. In a Colorado study, frequency of blue grama plants increased with
light, moderate, and heavy grazing levels while biomass decreased relative to
ungrazed areas . In a New Mexico study, blue grama density was not significantly
different between grazed and ungrazed sites. However, blue grama percent cover
was substantially higher on ungrazed sites than on grazed sites following a
severe drought . Clipping treatments to simulate grazing in New
Mexico did not result in significant changes (relative to controls) in blue
grama height or biomass at the end of the growing season, demonstrating the
ability of blue grama to recover quickly .
Trlica and others , however, found that blue grama required more than 26 months of
rest to recover its vigor following repeated heavy defoliations.
Frequent grazing or clipping of
blue grama may encourage top-growth; however, it may result in poor root growth
[45,94,322]. However, Santos and Trlica  found that frequent clipping (2- and 4-week
intervals) of blue grama resulted in reduced biomass of both crowns and root. Buwai and Trlica
[79,80] found that repeated defoliation
treatments did not impact root weight or carbohydrate reserves of blue
grama. The authors suggest that blue grama's resistance to clipping or grazing
may be related to its ability to maintain adequate root growth by transferring
more assimilated carbohydrate to belowground root production , or to the ability of defoliated plants to remain in a semi-dormant stage
throughout most of the growing season while unclipped plants use their stored
carbohydrates for growth . Grazing may also impact the reproductive ability of blue grama; Coffin and
Lauenroth  found that the average weight of reproductive structures was
greater and more than twice as many viable seeds were produced per flowering
culm on ungrazed than grazed locations.
Blue grama production generally responds positively to fertilizer inputs,
including nitrogen, phosphorus, potassium, and zinc [134,294,370,371,379]. Blue grama production (kg/ha) was significantly greater (p < 0.05) with
sludge application rates of 10, 20, and 40 tons per acre (22.5, 45, 90 Mg/ha)
During the 1st and 2nd growing seasons, yields ranged from 1.5 to 2.7 times
greater in the treated plots than in the unamended plots. Sludge amendments also
increased the nutritional value of blue grama, resulting in higher nitrogen,
phosphorus, potassium, and crude protein tissue concentrations. However,
Fresquez and others  found that while production increased with
applications of 10, 20, and 40 tons per acre (22.5, 45, 90 Mg/ha), only the 40-ton
(90 Mg/ha) treatment resulted
in significantly increased production compared to the control plots. Trace metals in
plant tissue did not increase significantly in either study [4,151].
In a New Mexico
study, blue grama height was significantly increased (p<0.05) with the
application of 40 pounds of nitrogen per acre (45 kg/ha) compared to the control. The 60
pounds per acre (67.5 kg/ha) application did not result in significantly greater heights than
the 40-pound treatment, and the density of blue grama increased significantly
(p<0.05) in response to each of the treatment levels . In a
greenhouse experiment, root and shoot biomass of blue grama increased with
addition of both nitrogen and phosphorus . In
contrast, Smoliak  found that blue grama basal areas decreased following
applications of nitrogen fertilizer and manure. Another study conducted in North Dakota found that blue grama
exhibited a decreasing trend in basal cover with increasing nitrogen application
rates . Nitrogen fertilization may also worsen the effects of
drought on blue grama .
Chemically thinning dense blue grama stands may result in increased herbage
and seed production . Blue grama is greatly reduced initially by applications of
atrazine, sylvex, picloram,
and 2,4-D [158,242]. However, within 5 years of picloram application, blue grama recovers vigorously, producing a large amount of foliage and many
seed heads . Atrazine applications, however, may also have
long-term negative effects on blue grama and soil processes . Germination of blue grama seeds may be
suppressed by applications of picloram and triclopyr . Atrazine, picloram, and 2,4-D may be useful in encouraging the
production or rapid establishment of
blue grama based on their control of competing plants [59,158,166,201].
Mechanical treatments (e.g. ripping and furrowing) result in decreased blue
grama production [169,361].
Prairie dog mound building in the Great Plains may result in a substantial
decrease in the size of blue grama clumps and patches, with blue grama cover
increasing as distance from prairie dog burrows increases. The prairie dog habit
of scratching topsoil from the area around burrows breaks larger patches of blue
grama into smaller clumps . Pocket-gopher disturbances also
have a lower basal cover (%) of blue grama than surrounding areas .
Cultivars, improved and selected materials (and area of origin)
Contact your local Natural Resources Conservation Service (NRCS:formerly Soil Conservation Service) office for more information. Look in the phone book under ”United States Government”. The Natural Resources Conservation Service will be listed under the subheading “Department of Agriculture.”
‘Lovington’ was released as a cultivar in 1963 by New Mexico AES and the Los Lunas Plant Materials Center. The original source of the material was a field harvest in 1944 near Lovington, New Mexico. It was bulk increased and tested as A-12424. It has uniform size, leafiness, excellent seedling vigor
and fast establishment characteristics.
‘Hachita’ was a cooperative release between the Los Lunas PMC and Colorado and New Mexico AES’s in 1980. Source material was originally collected in 1957 south of Hachita, New Mexico in a 250mm precipitation zone at an altitude of 1220 meters. It is the most drought tolerant of blue grama materials tested in New Mexico.
‘Alma’ was a cooperative cultivar release with USDA Agriculture Research Service, Los Lunas New Mexico PMC, and the Colorado and New Mexico AES’s in 1992. The cultivar was a composite of 270 plants from Hachita, Lovington and PMK-1483. The material was screened initially for heavier caryopsis weights, increased seedling vigor and greater emergence from deeper soil depths. Its intended use was for rangeland improvement and go back cropland seeding in southern and central Great Plains.
Bad River Ecotype blue grama was a selected release from the North Dakota PMC, North Dakota Association of Conservation Districts and the North and South Dakota AES in 1996. Its origin is Haakon County in central South Dakota on the floodplain of the Bad River. The intended use is the Northern Great Plains, USDA Plant Hardiness Zone 3. Bad River establishes readily and has consistent plant performance compared to native harvest materials.
To consistently produce grass seed of any species the most important first step is to obtain a uniform, clean stand of grass. Skips and thin spots in the row invite weeds and other competing species which will cause trouble later. Weeds must be controlled the year of seeding and in subsequent years. However, careful weed control the initial year of seeding will provide a more uniform stand in the seed field and less work in subsequent years.
Cultivation and herbicide applications along with hand weeding in the row will provide an even stand of grass that after the first year will provide reduced labor when harvesting, cleaning and processing the seed crop. The most important factor in producing blue grama seed is time of bloom. In Oklahoma, blue grama should bloom in September to fill completely (Harlan et al. 1956). If growth is promoted by early rain then seed field should be mowed several times or grazed heavily. The first inflorescences should be removed and the stand should be encouraged to remain vegetative until fall.
The first irrigation should be applied in mid-August along with the first nitrogen fertilization.
Once established this grass is palatable to livestock year around. Growing points of this grass are low and near the grounds surface, thus close grazing by livestock can be allowed. To obtain the best forage yields, grazing should be deferred once every two to three years. Blue grama cures well on the stem making it a good grass for deferred grazing during its dormant period. Weed control can be accomplished by mowing, controlled grazing or herbicide applications.
Relevance to Humans and Ecosystems
Value for rehabilitation of disturbed sites
Because of its wide adaptation, ease of establishment, and economic value, blue grama is used extensively for conservation purposes [106,199,349], rangeland seeding [15,65,178,200,247,284,334], and landscaping [55,195,315]. Blue grama is useful for reclamation [143,150,172,248,310,315] and for erosion control in arid and semiarid regions [58,315,334,349,365]. Blue grama growing on abandoned mine sites does not show any significant increase in metal uptake .
Excellent stands of blue grama have been achieved by broadcast or solid-drill seeding, with a seeding rate of 8 to 12 pounds per acre (9-13.5 kg/ha) [188,349], though others report that blue grama may be difficult to establish by seed . As a general rule, blue grama seeds should be used near their point of origin to achieve maximum planting success [188,349]. Planting depth of 0.25 to 0.5 inches (0.6-1.3 cm) is critical for successful establishment, and blue grama seedling emergence decreases with increased planting depth [74,85]. Redmann and Qi  found that blue grama seedling emergence was highest at a planting depth of 0.6 inches (1.5 cm), and emergence decreased to 0% when seeds were sown at 2.5 inches (6 cm). Increased planting depths may result in decreased shoot and root weights of emerging seedlings , while at shallower planting depths, the developing seedlings are most likely adversely affected by the rapid drying of the soil. However, heavier blue grama seeds may have greater emergence success from deeper planting depths than lighter seeds , which may allow them to take advantage of moisture for germination and emergence . Summer planting and a minimum of 13 inches (330 mm) of annual precipitation is recommended for successful blue grama establishment . Eddleman  also recommends planting blue grama seed after soil temperature has reached at least 50 degrees Fahrenheit (10 oC). With temperatures of 50 to 68 degrees Fahrenheit (10-20 oC), blue grama seeds germinated at rates of 85 to 91%. A blue grama germination rate of 88% was achieved with night/day temperatures of 60 to 70 degrees Fahrenheit (15-21 oC) and 86 to 95 degrees Fahrenheit (30-35 oC), respectively . Other research has found that more than 88% of blue grama seeds may germinate in about 2 days when subject to a range of alternating temperatures of 80 to 99 degrees Fahrenheit (27-37 oC) for 8 hours and 95 to 99 degrees Fahrenheit (35-37 oC) for 16 hours. Constant temperatures of 61, 81, and 99 degrees Fahrenheit (16, 27, and 37 oC) resulted in 100% germination in mean times of 6, 2.4, and 2 days, respectively. Moisture stress did not inhibit germination of blue grama until stress exceeded -10 bars .
If done early in the growing season, transplanting blue grama as sod may result in successful establishment. Sod should be 2 inches (5 cm) thick and wet before cutting; after transplanting, sod should be irrigated as soon as possible. In transplanting studies, 9-week-old blue grama plants were planted in the Sonoran Desert. Survival of blue grama averaged 80% after 2 months and declined to 21% after 32 months . Establishment depends mainly on new adventitious roots produced on recently developed tillers . Under controlled conditions, Briske and Wilson  found that temperature impacts blue grama root development, with the greatest number of roots initiated (per seedling) at 68 degrees Fahrenheit (20 oC) and the greatest root length and weight (per seedling) occurring at 86 degrees Fahrenheit (30 oC). The greatest shoot growth was also achieved at 86 degrees Fahrenheit (30 oC). Seed used in this experiment was taken from several locations in the Great Plains, and temperature treatments ranged from 41 to 95 degrees Fahrenheit (5-35 oC). Favorable soil moisture conditions also impact adventitious root development, so recommendations for good blue grama establishment include planting when 2 or more consecutive days of precipitation are likely or when temperatures are favorable for emergence and root growth even if consecutive "wet" days are unlikely.
Blue grama is poor cover for upland game birds and waterfowl, and fair to poor cover for small mammals . Blue grama provides fair nesting cover and is important to some prairie songbirds . The blue grama/kleingrass (Panicum coloratum) cover type in the southern high plains of Texas provides high-quality nesting habitat for ring-necked pheasants, contributing to increased nest success, high nest density, and increased pheasant production . Blue grama and buffalo grass flats provide good nesting sites for mountain plovers in Montana, Wyoming, and Colorado , and important herbaceous cover for quail in Texas .
Importance to Livestock and Wildlife
Blue grama is valuable forage for all classes of domestic livestock [87,315,349,355], providing excellent forage for cattle and sheep [73,153,293,351]. Blue grama makes up as much as 40% of the diet of cattle on the shortgrass steppe [16,353]. Blue grama tends to be most productive following summer rains, but it cures well and provides forage year round [191,192,274]. In the northern Great Plains, cattle graze blue grama in both summer and early fall [133,351]. Currie and others  found that blue grama became increasingly important in cattle diets late in the season, from August to November, in Central Colorado. Another study found that blue grama was utilized more by cattle from June through March than during spring months . Domestic sheep in Utah use blue grama from spring through fall . As a low growing grass, blue grama may be unavailable during the winter due to snow cover [168,187]. Blue grama is widely used for pasture and less often for hay .
Blue grama also provides important forage for mule deer [72,224]. However, in a study on the prairie of north-central Montana, mule deer were not found to browse blue grama, instead favoring forbs and shrub species . Blue grama provides important winter forage for elk in Colorado , and provides good forage for pronghorns during all seasons in western Texas and in Kansas [73,273]. Blue grama is only lightly browsed by pronghorn in Utah and Colorado, with use occurring primarily in the spring [36,313]. Blue grama is important summer forage for bighorn sheep in Colorado . It is also an important forage for bison [260,276], and blue grama development plays a role in seasonal bison movements .
Scaled quail and some songbirds eat the seeds of blue grama . Small mammals also eat blue grama seeds and stems [110,186], providing an important food source for prairie dogs, pocket gophers, and black-tailed jackrabbits in the Great Plains [54,132,142,273,338,352]. Flower heads and seeds of blue grama are also consumed by grasshoppers, which can all but eliminate an annual seed crop [71,222].
When blue grama is green, the leaves are low in fiber and high in protein. It may retain up to 50% of its nutritive value when dormant
, and retains approximately 5% protein when dormant . In Colorado, crude protein content of live blue grama averages 10%
throughout the year, with the highest content (18%) occurring during early in
the growing season and the lowest content (8%) occurring just prior to dormancy. Crude protein content does not respond to different
grazing intensities (ungrazed, light, moderate, and heavy grazing) . Fudge and Fraps
 found that protein content of blue grama
ranged from 3.3 to 9.8% in Texas, fair to good for cattle forage. In Oklahoma, crude protein of blue grama may range from 4.4% to 17.0%,
calcium may range from 0.17% to 0.48%, and phosphorus may range from 0.07% to
0.31% . The percent composition of air-dried blue grama in Arizona is presented below
|water||ash||crude protein||crude fiber||fat||N-free extract|
Nutrient content of blue grama in an Oklahoma plains grassland is presented
below. Data is presented in percent of oven-dry weight and represents means over
5 years :
|Ca||P||Protein||Fat||N-free extract||crude fiber||ash|
Average nutrient concentrations (with standard deviation) of blue grama in a
Central Plains saltgrass meadow were as follows :
Nitrogen concentration of senescent blue grama foliage has been reported as
approximately 1% of the dry weight . Calcium,
phosphorus, crude protein, iron, manganese, and magnesium in blue grama decrease with maturity,
though some of these declines may be
halted or mitigated by periods of precipitation [289,331].
Nitrogen fertilization of blue grama rangeland may result in increased
digestibility of dry matter, crude protein, copper, crude fiber, and lignin in blue
grama [216,279]. However, nitrogen fertilized blue
grama may contain less calcium and aluminum than unfertilized blue grama .
. The following table presents livestock palatability ratings for blue
Forage: A highly palatable grass for livestock on a year long basis. It is used sparingly by antelope and other wildlife species. Blue grama rates with buffalograss as one of the most important forage plants of the short-grass prairie (Weaver, 1926)
Erosion control: Blue grama can be used in mixtures with other grasses for use in erosion control situations. It is commonly used as a low maintenance turf planting, such as rough areas of a golf course or between rows in multiple row wind break plantings and in locations prone to drought. It is also used in surface mine re-vegetation plantings.
Bouteloua gracilis (blue grama) is a long-lived, warm-season, C4 perennial grass, native to North America. It is most commonly found from Alberta, Canada, east to Manitoba and south across the Rocky Mountains, Great Plains, and U.S. Midwest states to Mexico. Blue grama accounts for most of the net primary productivity in the shortgrass prairie of the central and southern Great Plains. It is a green or greyish, low-growing, drought-tolerant grass with limited maintenance.
The Bouteloua gracilis plant height at maturity ranges from 15–30 centimetres (6–12 in). The roots generally extend 30–46 centimetres (12–18 in) from the edge of the plant, and 0.9–1.8 metres (3–6 ft) deep. Maximum rooting depth is approximately 2 metres (7 ft). Blue grama is green to greyish in appearance.
Blue grama is readily established from seed, but depends more on vegetative reproduction via tillers. Seed production is slow, and depends on soil moisture and temperature. Seeds dispersed by wind only reach a few meters (~6 ft); farther distances are reached with insects, birds, and mammals as dispersal agents. Seedling establishment, survival, and growth are greatest when isolated from neighboring adult plants, which effectively exploit water in the seedling's root zone. Successful establishment requires a modest amount of soil moisture during the extension and development of adventitious roots.
Established plants are grazing-, cold-, and drought-tolerant, though prolonged drought leads to a reduction in root number and extent. They employ an opportunistic water-use strategy, rapidly using water when available, and becoming dormant during less-favorable conditions. In terms of successional status, blue grama is a late seral to climax species. Recovery following disturbance is slow and depends on the type and extent of the disturbance.
Horticulture and agriculture
Blue grama is valued as forage.
Bouteloua gracilis is grown by the horticulture industry, and used in perennial gardens; naturalistic and native plant landscaping; habitat restoration projects; and in residential, civic, and highway erosion control. Blue Grama flowers are also used in dried flower arrangements.
|Wikimedia Commons has media related to Bouteloua gracilis.|
- "PLANTS Profile for Bouteloua gracilis (blue grama)", Plants.USDA.gov, June 2012, webpage: Bogr2: has classification; map of North America in 30 U.S. states.
- "Blue Grama - Animal & Range Sciences", Montana Univ., AnimalRangeExtension.Montana.edu, 2011, webpage: MBlue.
- Stevenson, Matilda Coxe 1915 Ethnobotany of the Zuni Indians. SI-BAE Annual Report #30 (p. 83)
- USDA NRCS plant profile: Bouteloua gracilis
- Anderson, M.D. 2003. U.S.D.A. Fire Effects Information System: Bouteloua gracilis - Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer).
|Wikispecies has information related to: Bouteloua gracilis|