General: Side-oats grama is a deep rooted, perennial grass. The plants crown will spread very slowly by means of extremely short, stout rhizomes. A mid-grass in height, it has rather wide leaves and a very distinct inflorescence consisting of a zigzag stalk with small compressed spikes dangling from it at even intervals. The short spikes dangle from one side of the stalk, thus providing the plant with its common name. In the vegetative state the grass is easily recognized by the long, evenly spaced hairs attached to the margins of the leaf near its base. Side-oats grama possesses the C-4 photosynthetic pathway common to warm-season grasses (Waller and Lewis, 1979).
Distribution: For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site. One of the most widely distributed of the grama grasses. It has a widespread distribution eastward from the Rocky Mountains to near the east coast except in the southeast.
Habitat: Side-oats grama grows effectively in the dryer mid-grass prairie section of the Great Plains that has an annual rainfall of 12-20 inches. This species occurs naturally in mixed stands with blue grama (Bouteloua gracilis) and little bluestem (Schizachyrium scoparium). This grass is better adapted to calcareous and moderately alkaline soils than to neutral or acidic soils (Leithead etal., 1971)
Range and Habitat in Illinois
Regularity: Regularly occurring
Regularity: Regularly occurring
Global Range: Widespread from Maine and Ontario west to Saskatchewan and Washington, south to Florida, and west to California (Kartesz 1999).
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 :
3 Southern Pacific Border
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
Side-oats is adapted to a broad range of sandy to clayey textured soils; it is least tolerant of loose sands and dense clays. The best stands of side-oats are found on medium to fine texture upland soils. This species has shown varying tolerance to soil salinity from weak to moderate. Side-oats is moderately drought tolerant, but less than blue grama. It is moderately tolerant of semi-shaded conditions and can be found in open woodlands. It will sustain damage from wildfires when actively growing and under drought stress conditions, but is fairly tolerant of fire in a dormant state. It is also fairly tolerant of spring flooding. It probably has the widest range of adaptation of any of the warm-season perennial grass plants. It grows in combination with tall warm-season grasses such as big bluestem (Andropogon gerardii) and switchgrass (Panicum virgatum) all the way to the short grass plants such as buffalo grass (Bouteloua dactyloides) and blue grama (Boutelouagracilis). Thus, it can successfully grow in a variety of climates and habitats in the continental U.S.
Sideoats grama is a native, warm-season perennial grass that grows 3 to 39 in (8-100 cm) tall [78,196]. Bouteloua curtipendula var. curtipendula culms occur singly or in small clusters from creeping rhizomes, while B. curtipendula var. caespitosa culms are in large clumps arising from a common root crown . Sideoats grama leaves are 0.11 to 0.15 inch (3-4 mm) wide and flat at maturity [78,93]. Inflorescences are elongate and may bear over 20 and up to 80 deciduous spikes [49,78,105], each of which bears 3 to 8 spikelets hanging to one side [78,93,128]. The fruit is an awnless caryopsis .
Sideoats grama typically has many coarse, fibrous roots , which may grow 2 to 4 feet (0.6-1.2 m) in length and spread laterally 1 to 1.5 feet (0.3-0.5 m) in the top 2 to 4 inches (5-10 cm) of soil . In a Nebraska study sideoats grama plants had a range of 170 to 423 roots per plant . Roots of sideoats grama are well adapted to growth in dry conditions . They extend rapidly into wet subsurface levels, reducing plant dependency on more variable moisture conditions at the surface soil . More information on drought resistance of sideoats grama is included in Management Considerations.
Catalog Number: US 2307994
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): T. Haenke
Locality: Acapulco., Mexico, Central America
- Type collection: Michaux, A. 1803. Fl. Bor.-Amer. 1: 59.
Catalog Number: US 2307994
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): T. Haenke
Locality: Acapulco., Mexico, Central America
Catalog Number: US 1063204
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Status verified by specimen annotations only
Preparation: Pressed specimen
Collector(s): -. Drummond
Locality: Texas, United States, North America
- Type fragment: Hooker, J. D. 1847. Trans. Linn. Soc. London. 20: 174.
Range and Habitat in Illinois
Sideoats grama is widely distributed across the plains, prairies, and lower mountains of much of North America [42,93]. It grows on a wide variety of landforms and habitats, but is most abundant and important in the central and southern mixed-grass prairies .
Elevation: Sideoats grama occurs at a wide elevational range that varies with location. In the southwestern United States, it is found from 3,000 to 8,000 feet (914-2,440 m) elevation . Ranges are similar for both varieties. Bouteloua curtipendula var. curtipendula occurs at elevations of from less than 328 feet (100 m) in southern Texas to over 8,200 feet (2,500 m) in the northwestern United States. Bouteloua curtipendula var. caespitosa occurs from 650 to 8,200 feet (200-2,500 m) . The following table provides a summary of the elevational ranges for sideoats grama:
|AZ||below 2,500 feet to 7,500 feet (760-2,130 m) [96,197]|
|CA||below 6,230 feet (1,900 m) |
|CO||3,500 to 7,500 feet (1,070-2,130 m) |
|NM||5,500 to 7,500 feet (1,680-2,130 m) |
|SD||1,265 to 1,493 feet (386-455 m) |
|UT||3,215 to 8,000 feet (980-2,440 m) |
Climate/moisture regime: Sideoats grama grows under a wide variety of climate conditions. A study of establishment of seeded-in grasses in pinyon-juniper woodlands in Arizona and New Mexico found sideoats grama was adapted to warm-moist and hot-dry sites, but not cold, cool, warm-dry, or hot-moist sites . A study of water-use of plains grasses suggests sideoats grama requires a fairly large supply of water for limited periods. Sideoats grama showed inefficient water-use relative to other plains grasses, especially in cold weather . According to Fulbright and others , sideoats grama has a low soil moisture requirement, but requires at least 15 inches (380 mm) of annual precipitation. Story  reported good stands of sideoats grama developed in areas with 12 to 16 inches (305-406 mm) of annual rainfall in the Southwest. In the central Great Plains, stand development of sideoats grama was greatest on fine-textured upland soils with 17 to 20 inches (432-508 mm) of annual rainfall. On Wisconsin prairie and savannas, sideoats grama occurs on sites characterized by cyclic mild to severe summer drought, less than 45 inches (1140 mm) annual snowfall, and a mean summer temperature of 68 degrees Fahrenheit (20 Â°C) .
Soils/landform: Sideoats grama is adapted to a broad spectrum of soils, from sands to clays [86,212]. It is least adapted to loose sand and dense clay, and has best stand development on medium to fine-textured soils . Sideoats grama grows on shallow to deep soils. It does not grow well on wet soils, although it is moderately tolerant of spring flooding . In the Intermountain West, sideoats grama grows well on sandy loam to clay loam . In North Dakota it is found on shallow soils with textures ranging from loamy sands through loams and silt loams to silty clay loams . Sideoats grama is an important component of grasslands on clay soils in the northern Great Plains  and on loess soils in the central Great Plains . In Kansas shortgrass prairie sideoats grama grows on fine-textured, silty clay loams, especially in areas with deep soils . Bush and Van Auken  reported sideoats grama aboveground, belowground, and total dry mass increased with increasing soil depth of up to 71 inches (180 cm).
Sideoats grama has weak to moderate tolerance to saline soils  but does well on calcareous or alkaline soils [68,122,140]. It often occurs on shallow limestone or dolomite soils  and on soils high in available nitrate. Sideoats grama is associated with moderate levels of soil water stress relative to other grama species . In mixed-grass prairie of northern Wyoming and southern Montana, it occurs on shallow soils with low water-holding capacity and high infiltration rate, and does well with relatively high growing season precipitation and no available groundwater .
Studies in Texas provide information about the soil requirements of the different varieties of sideoats grama. Bouteloua curtipendula var. curtipendula grows mostly on loose, limey soils and on relatively good soils in less disturbed areas including native Texas prairies , while B. curtipendula var. caespitosa has higher cover on soils with higher clay content, pH, and organic matter . However, according to Gould , Bouteloua curtipendula var. curtipendula grows best on loamy, well-drained soils, while B. curtipendula var. caespitosa is usually found on loose, sandy or rocky, well-drained limey soils.
Sideoats grama is well-adapted to steep, rocky slopes [50,122,154,205]. In Illinois sideoats grama is found in coarse soil on limestone outcrops [7,20,193]. It occurs on shale barrens in West Virginia . Sideoats grama is common in washes and on low benches . In the Southwest it grows on south- to west-facing slopes, dry hills, and mesas [105,128,197].
Key Plant Community Associations
Sideoats grama generally occurs in dry woods in the eastern United States and in
dry prairies and sandhills in the western states .
It is a major species in grasslands of the Great Plains, including tallgrass
prairie [113,174], mixed-grass prairie and shortgrass steppe [110,118], and in desert grasslands of the
Southwest . Sideoats grama
is also found in ponderosa pine (Pinus ponderosa) forests, eastern hardwood
savannas , southwestern oak (Quercus
spp.) and pinyon-juniper (Pinus-Juniperus spp.) woodlands and
savannas [112,165], and desert and semidesert
shrublands . Sideoats grama is commonly associated with bluebunch wheatgrass (Pseudoroegneria spicata),
western wheatgrass (Pascopyrum smithii), little bluestem (Schizachyrium
scoparium), big bluestem (Andropogon gerardii var. gerardii),
Idaho fescue (Festuca idahoensis), prairie Junegrass (Koeleria
macrantha), blue grama (Bouteloua gracilis), black greasewood (Sarcobatus
vermiculatus), true mountain-mahogany (Cercocarpus montanus),
southwestern oaks, Colorado pinyon pine (Pinus edulis),
and several juniper species including redberry juniper (Juniperus pinchotii),
eastern redcedar (J. virginiana), oneseed juniper (J.
monosperma), Ashe juniper (J. ashei), alligator juniper (J.
deppeana), and Utah juniper (J.
The following list of publications includes selected classifications listing
sideoats grama as an indicator or dominant species in vegetation classifications.
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, vine
SRM (RANGELAND) COVER TYPES :
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
604 Bluestem-grama prairie
611 Blue grama-buffalo grass
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
711 Bluestem-sacahuista prairie
712 Galleta-alkali sacaton
715 Grama-buffalo grass
717 Little bluestem-Indiangrass-Texas wintergrass
720 Sand bluestem-little bluestem (dunes)
721 Sand bluestem-little bluestem (plains)
724 Sideoats grama-New Mexico feathergrass-winterfat
725 Vine mesquite-alkali sacaton
727 Mesquite-buffalo grass
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 :
42 Bur oak
46 Eastern redcedar
66 Ashe juniper-redberry (Pinchot) juniper
67 Mohrs (shin) oak
236 Bur oak
237 Interior ponderosa pine
240 Arizona cypress
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
KUCHLER  PLANT ASSOCIATIONS:
K016 Eastern ponderosa forest
K017 Black Hills pine forest
K023 Juniper-pinyon woodland
K031 Oak-juniper woodland
K032 Transition between K031 and K037
K037 Mountain-mahogany-oak scrub
K053 Grama-galleta steppe
K054 Grama-tobosa prairie
K058 Grama-tobosa shrubsteppe
K060 Mesquite savanna
K065 Grama-buffalo grass
K068 Wheatgrass-grama-buffalo grass
K069 Bluestem-grama prairie
K070 Sandsage-bluestem prairie
K074 Bluestem prairie
K075 Nebraska Sandhills
K076 Blackland prairie
K081 Oak savanna
K083 Cedar glades
K084 Cross Timbers
K085 Mesquite-buffalo grass
K086 Juniper-oak savanna
K087 Mesquite-oak savanna
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):
FRES21 Ponderosa pine
FRES30 Desert shrub
FRES32 Texas savanna
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
FRES38 Plains grasslands
FRES40 Desert grasslands
Habitat & Distribution
Seed improved cultivars of this grass no deeper than ¼ inch on fine textured soils and ¾ inch on coarser textured soils. Planting with a grass seed drill on a firm, weed free seedbed at the rate of 2.5 to 5.0 pounds of pure live seed (PLS) is encouraged. Broadcasting at a higher seeding rate (50 to 100 percent increase) can be utilized on a previously prepared seedbed that will be culti-packed after seeding is completed. Increased seeding rate should also be used on bare areas, harsh sites, or on areas that require denser or quicker stand establishment. Seeding is more likely to be successful if moisture conditions are good and if mulch is used to retain moisture on the seeding site. Most seed germinates within 7 days under good field conditions. Seedling vigor is good when compared to other warm season grasses. Field germination, emergence and establishment of this species are better than other grama grasses. Protection from grazing is encouraged while seedlings are in the juvenile stage of growth.
Fire Management Considerations
Spring burning appears to be most beneficial to sideoats grama [4,6,88]. Site characteristics should be part of a fire management plan for sideoats grama. Fire is more beneficial in relatively humid, more productive grasslands than in drier, less productive sites, partially because litter buildup in more productive communities can reduce sideoats grama productivity, while litter improves moisture-holding capacity of soil in drier sites [114,163]. Studies indicate that sideoats grama generally increases after fire on relatively mesic prairie sites [25,53,190,199,228] but shows a short-term decrease following fire on more arid grasslands of the Southwest [1,21,33,220]. Burning every 4 to 5 years appears to benefit sideoats grama more than more frequent burning [38,175].
Broad-scale Impacts of Plant Response to Fire
Site grazing and fire history is likely to affect the response of grasses
to fire. In an unfinished manuscript, Hulbert (as presented in Gibson )
specified 6 to 10 years of mowing and burning treatments are not sufficient
to remove all effects of prior burning and grazing, which may influence fire
behavior and effects on sideoats grama.
The response of sideoats grama to fire varies with time of burning. Several
studies report favorable response of sideoats grama to spring burning. Sideoats grama increased under
annual early spring burning of grassland pasture . In Kansas bluestem prairie, Aldous
 studied response to several annual burning treatments conducted after rains, when
wet ground protected the root crowns of dominant grasses.
The number of sideoats grama plants doubled in 6 years under early spring
burning; increased under mid-spring burning; increased by more than a 3rd of
the original number of plants in the late spring-burned plot; but showed little
change on the fall-burned and unburned plots . In Wisconsin late-spring fire enhanced flowering of sideoats
grama more than did an early spring fire, and resulted in a greater
postfire increase in flowering on
the mesic site compared to the drier site. In the first 2 years of the
study, sideoats grama averaged a 250% increase in flowering after early spring burning and 600%
after late spring burning on dry-mesic plots. Increases in flowering on the dry
site were 60% and 150% for early and late spring burns, respectively . McMurphy  compared percent basal cover
of sideoats grama on plots burned annually in March with those
burned in April or May, and with unburned plots, over 12 years. On
the "ordinary upland" site with medium- or loam-textured soil, the unburned pasture consistently had a lower
percent of sideoats grama than the burned plots, although the differences were only significant
(p<0.05) between unburned and early (March) burn sites, and not significant in all
years. There was no apparent trend between burned and unburned plots on the
limestone breaks site. On the claypan site, late spring (May) burned and early
(March) burned pastures supported significantly more (p<0.05) sideoats grama than the mid-spring
(April) and unburned plots. In contrast, Henderson  compared an unburned plot with
3 plots with 3 different fire treatments (late fall, early spring, and late spring burn),
and found no significant difference in frequency of occurrence of sideoats grama
among plots. The author specifies that due to the abundance of sideoats grama,
only dramatic declines would have been detected by the frequency of occurrence
Sideoats grama increased following early spring burns in eastern Kansas 
and in southern Nebraska. The table below compares the herbage yield of sideoats
grama harvested in June and September from burned and mowed plots :
|Herbage yield (kg/ha) by |
|Harvest date||Burned (April 25, 1980)||Mowed (September 1979 and 1980)||Control|
Plant Response to Fire
Sideoats grama recovers from burning by tillering and/or rhizomatous spread (in Bouteloua curtipendula var. curtipendula), and by establishing from seed . Awnless seeds may be carried by wind  into burned areas for natural reestablishment, and the nutrient-rich postfire environment may encourage mass flowering in postfire year 2 or 3 .
The response of sideoats grama to fire varies with growth form, fire frequency and severity, season of burn, climatic conditions, and composition of associated plant community. Fire generally favors the bunchgrass variety, Bouteloua curtipendula var. caespitosa. The rhizomatous variety of sideoats grama (Bouteloua curtipendula var. curtipendula) generally decreases after fire, particularly in dry years. It may require 3 or more years for full recovery . In wet years the rhizomatous variety tolerates fire "reasonably well" . Several studies have documented the response of sideoats grama to fire. Results vary by study and are summarized below.
Sideoats grama appears to respond most favorably to fire at approximate 5-year intervals. In southeastern Arizona, Robinett and Barker  studied the response of several grass species in areas subjected to different fire frequencies during the hot season (May through July). Species composition on plots subjected to 1 fire, 2 or 3 fires, or 5 or 6 fires over 15 years was compared on sites with different soil textures and other site characteristics. On the Loamy Hills and Granitic Hills sites, sideoats grama had greatest percent cover relative to other species on plots that were burned 3 times over the 15-year period, compared to sites burned only once or those burned 5 or 6 times during that time. On the Sandy Loam Upland site, frequency of sideoats grama was approximately 40% on the 1-burn site and declined to less than 5% on sites subjected to 3 or 5 burns in the 15-year period. Decadence of sideoats grama was observed on sites burned only once. A similar trend in response of sideoats grama to different fire frequencies was reported by Collins and others  on the Konza Prairie in northeastern Kansas. Average cover of sideoats grama was highest (4.9%) in plots burned every 4 years, compared to 3.1% on plots burned annually and 1.6% on unburned ploys. However, sample sizes were small (n = 2 or n = 3) and significance of differences in cover of sideoats grama was not reported. Becker  found sideoats grama increased over 5 years on plots burned annually at low to moderate severity on a blue grama-little bluestem prairie in southwestern Minnesota.
Several studies indicate that site characteristics influence the response of sideoats grama to fire. In the Molino Basin of southern Arizona, Caprio  compared vegetation on unburned sites with sites burned in June 1983. He found cover of sideoats grama increased following burning on south and east slopes, but declined on the north slope. Fire severity was not specified. Pemble and others  reported flowering of sideoats grama was stimulated by fire on a dry, hilly, undisturbed prairie site, inhibited on a mesic, level, undisturbed site, and showed no significant increase or decrease (p > 0.05) on a mesic, gently sloping to level site. Litter was almost completely consumed on dry hilly site, but considerable litter remained in depressions on the wetter sites. Fire severity was not specified. In 1937, Leopold  compared vegetation of Mexico and the United States. He concluded that the Sierra Madre of Chihuahua, Mexico, supported comparatively lush stands of sideoats grama because of frequent fires and light grazing. Across the border, fire suppression and overgrazing had already reduced sideoats grama cover in the United States by that time.
Fire response of sideoats grama is partially dependent on the response of competing species. Cover of sideoats grama decreased after burning treatments on a big bluestem-porcupine grass (Hesperostipa spartea) tallgrass prairie in Iowa. The site had been mowed prior to the experiment, allowing sideoats grama to maintain an artificially high cover. After burning without follow-up mowing, the tall grasses provided more competition. In contrast, sideoats grama increased or remained essentially the same on a loess hills prairie site . On a tallgrass prairie site in Kansas, stem density of sideoats grama was reduced after 3 years without burning on both deep- shallow-soil plots .
Burning prior to seeding can help establishment of sideoats grama. When used for revegetating stands dominated by exotic Lehmann lovegrass (Eragrostis lehmanniana), sideoats grama had higher seedling density after seeding on a burned plot than on plots sprayed with herbicide prior to seeding, although the difference among plots was only significant (p<0.05) for the late-season (August) planting in 1 year . Reseeding of prescribed burned areas resulted in "especially good establishment" of sideoats grama in Great Basin shrubsteppe area of northwestern Arizona .
Several studies, most from the southwestern United States, have found a short-term decrease in sideoats grama after burning. Cover of sideoats grama "decreased dramatically" after a wildfire in a desert mountain scrub community in Texas, determined by comparing vegetation on burned and unburned plots at postfire year 2 . Frequency of sideoats grama was less on 3-year-old burns than on unburned sites in the Guadalupe Mountains of New Mexico. Fire severity was not specified, but fuels were estimated at < 0.5 ton/acre for litter and cured grasses and 7 tons/acre for living vegetation . On Arizona range sites sideoats grama often declines in the season or year immediately following burning but recovers in subsequent years [21,220]. This fire response was documented in 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 Bock and Bock's  work for more information on burning conditions, fires, and fire effects on more than 100 species of herbaceous and woody plants, birds, small mammals, and grasshoppers.
In some cases burning may have little or no effect on sideoats grama. In a study in Wind Cave National Park, South Dakota, Bock and Bock  measured plant height of several graminoid species before and after burning with "relatively cool" surface fires. Height of sideoats grama did not differ significantly (p < 0.05) in any year between burned and unburned control plots. Sideoats grama showed no difference in flowering response between burned and unburned stands in Wisconsin . Fire severity was not specified, but the 2.3-inch (5.8-cm) mulch layer was completely removed by the fire.
Fire can increase nutritional value of sideoats grama. Iron, phosphorus, and zinc concentration in sideoats grama increased with increasing fire frequency, although trends in nutrient increase were not all statistically analyzed. The effects of fire frequency on nutrient concentrations in sideoats grama are summarized in the table below :
|Consecutive years burned||0||1||2||3||4|
|Total N (%)||0.50||0.54||0.52||0.50||0.55|
For more information about the nutritional value of sideoats grama, see Management Considerations.
Broad-scale Impacts of Fire
The immediate effect of fire on sideoats grama varies seasonally with differences in air temperature and plant desiccation. A study in Arizona indicated that lethal temperatures at culm bases of sensitive perennial grasses such as sideoats grama closely approximate existing air temperatures at or near ground level during hot dry months of summer. During cooler, moister periods, when plant material is less desiccated, lethal temperatures at culm bases are much higher. Over the 2-year study, the lethal temperatures for sideoats grama ranged from 138 to 154 degrees Fahrenheit (58.8-73.7 Â°C) .
Immediate Effect of Fire
POSTFIRE REGENERATION STRATEGY :
Rhizomatous herb, rhizome in soil
Initial off-site colonizer (off-site, initial community)
Secondary colonizer (on-site or off-site seed sources)
Fire adaptations: Sideoats grama establishes after fire through seed and/or lateral spread by rhizomes and tillers. Recovery often takes 2 to 3 years [227,228] and varies with site conditions, burning frequency, and plant growth form (see Fire Effects). Sideoats grama fruits lack an awn; therefore, initial seed dispersal onto burned sites is effected primarily by wind. Postfire seed production may increase after burning. In Wisconsin, flowering of sideoats grama increased after spring burns  (see Fire Effects). However, another Wisconsin study found no increase in flowering of sideoats grama after an April wildfire  .
FIRE REGIMES: Grassland and shrubland ecosystems where sideoats grama is important historically experienced frequent, stand-replacement fire. FIRE REGIMES are highly variable across sideoats grama's wide distributional range, however. In plains grassland communities where sideoats grama is important, historic fire return intervals ranged from less than 10 years up to 35 years. Return fire intervals for desert grassland communities with sideoats grama ranged from 1 to 100 years, and some shrub-dominated communities with sideoats grama had historic fire return intervals of 100+ years . FIRE REGIMES for plant communities and ecosystems in which sideoats grama occurs are summarized in the table below. For further information regarding FIRE REGIMES and fire ecology of communities where sideoats grama is found, refer to the 'Fire Ecology and Adaptations' section of the FEIS species summaries for the community and ecosystem dominants listed below.
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|bluestem prairie||Andropogon gerardii var. gerardii-Schizachyrium scoparium||< 10 [114,163]|
|Nebraska sandhills prairie||A. gerardii var. paucipilus-S. scoparium||< 10|
|bluestem-Sacahuista prairie||A. littoralis-Spartina spartinae||< 10|
|desert grasslands||Bouteloua eriopoda and/or Pleuraphis mutica||5-100|
|plains grasslands||Bouteloua spp.||< 35 |
|blue grama-needle-and-thread grass-western wheatgrass||B. gracilis-Hesperostipa comata-Pascopyrum smithii||163,180,229]|
|blue grama-buffalo grass||B. gracilis-Buchloe dactyloides||< 35|
|grama-galleta steppe||Bouteloua gracilis-Pleuraphis jamesii||< 35 to < 100|
|blue grama-tobosa prairie||B. gracilis-P. mutica||< 35 to < 100|
|mountain-mahogany-Gambel oak scrub||Cercocarpus ledifolius-Quercus gambelii||< 35 to < 100|
|juniper-oak savanna||Juniperus ashei-Q. virginiana||< 35|
|Ashe juniper||J. ashei||< 35|
|cedar glades||J. virginiana||3-7|
|Colorado pinyon||P. edulis||10-400+ [64,75,106,163]|
|interior ponderosa pine*||P. ponderosa var. scopulorum||2-30 [9,10,121]|
|mesquite-buffalo grass||P. glandulosa-Buchloe dactyloides||< 35|
|Texas savanna||P. glandulosa var. glandulosa||163]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||163]|
|bur oak||Q. macrocarpa||210]|
|oak savanna||Q. macrocarpa/Andropogon gerardii-Schizachyrium scoparium||2-14 [163,210]|
|shinnery||Q. mohriana||< 35|
|little bluestem-grama prairie||S. scoparium-Bouteloua spp.||< 35 |
More info for the terms: climax, codominant, cover, rhizome, secondary colonizer, succession
Sideoats grama occurs in all stages of succession. It is moderately shade tolerant , growing in partial shade to full sun [36,136,183,212]. In ponderosa pine woodlands of northwestern Nebraska, the importance of sideoats grama relative to other grass species increases with increasing canopy cover, indicating that sideoats grama is relatively shade tolerant . Bolander  found sideoats grama in Arizona chaparral was moderately dense where the canopy was open and grazing was not been heavy.
Sideoats grama can be a primary or secondary colonizer on burned areas. Seeds are carried into burned sites by wind or produced by plants surviving fire . Sideoats grama occurs in early seral postfire communities  and increases on disturbed sites through asexual regeneration or self-seeding [210,213]. Sideoats grama seeds more successfully on burned than unburned sites [18,19], indicating it colonizes after disturbance by fire. It may increase in cover immediately following fire [134,190], indicating it can also spread by tillering or rhizome expansion. Leopold  described sideoats grama communities maintained by frequent fires in areas relatively undisturbed by grazing.
Sideoats grama is a climax indicator in arid grasslands throughout the Southwest , and is a dominant or codominant species in late-seral vegetation across much of the Great Plains . Dodd and Holtz  list sideoats grama as a dominant component in late-seral grassland vegetation on a loam range site in southern Texas.
Breeding system: Sideoats grama reproduces apomictically or sexually . Apomixis occurs in the southern range of sideoats grama, most commonly within the range of Bouteloua curtipendula var. caespitosa. Sideoats grama has perfect flowers  that cross pollinate .
Pollination: In plants reproducing sexually, cross pollination is effected by wind .
Seed production: Sideoats grama produces a "fair amount of seed of rather low viability"  but seeds readily when adequate moisture is available . There are several cultivars of sideoats grama (see Management Considerations) with varying seed productivity.
Seed dispersal: Awnless fruits suggest that sideoats grama seed is dispersed mainly by wind .
Seed banking: Little direct information is available about seed banking of sideoats grama, but several studies indicate that seed banking of sideoats grama is minor, and varies with local conditions. A study of seed banks in postsettlement vegetation communities in the Loess Hills of Iowa found sideoats grama had low seed density (<25 seeds/m2) in the seed bank of a shrubland site dominated by shrubby roughleaf dogwood (Cornus drummondii) and elm (Ulmus spp.), but moderate seed density (25-100 seeds/m2) in a grassland site dominated by Kentucky bluegrass (Poa pratensis) and smooth brome (Bromus inermis) . Seeds of sideoats grama were not encountered in the seed bank of a deciduous woodland site dominated by tree-size roughleaf dogwood and elm. Examination of Texas seed banks in plots managed with long-term (36-year) grazing Texas revealed seeds of sideoats grama appeared to be transient and were not stored in seed banks. Sideoats grama was part of the historic vegetation: savanna dominated by caespitose mid-grasses including sideoats grama, Texas tussockgrass (Nassella leucotricha), Texas cupgrass (Eriochloa sericea), and little bluestem, with associated short grasses including curlymesquite (Hilaria belangeri) and hairy woolygrass (Erioneuron pilosum), and scattered clumps or individuals of oak (Quercus spp.) and Ashe juniper . Sideoats grama's cover was not specified, although the authors did state late-seral mid-grasses had been reduced by grazing. In a study testing seed viability in Kansas prairie communities, soil samples taken from a mid-grass community dominated by sideoats grama yielded only 2 sideoats grama germinants .
Seed dormancy can affect timing of germination. Germination rate of sideoats grama seed from 148 sources ranged from 18% for the most dormant seed to 96% for the least dormant . Major and Wright  found after the postharvest period, dormancy was completely broken in sideoats grama seed when floral parts were removed from caryopses. Germination was highest for seed with the heaviest caryopses, and fewer caryopses per gram. Dormancy may be controlled by "coumarin-like" inhibitory compounds.
Germination: A number of studies have focused on germination requirements of sideoats grama. These studies reveal that germination rates of sideoats grama vary with place of seed origin, as well as with temperature regimes, moisture, and other conditions. Sideoats grama seed vigor is good compared to seeds of other warm-season grasses . When conditions are favorable, germination is rapid; in 1 case sideoats grama showed 50% germination within 22 hours . Studies have found differing results for germination success rate. Halinar  reported germination rates of 20 to 30% and 18 to 34% in 2 consecutive years. Other sources found 50 to 70% germination [40,68]. Jordan and Haferkamp  found high sideoats grama germination success, ranking 3rd out of 19 warm-season grasses tested. Wasser  stated most sideoats grama seed germinates within 7 days under ideal field conditions. Light improves germination .
Heat affects rate and success of sideoats grama germination. Temperatures between 50 and 86 degrees Fahrenheit (10 and 30 Â°C) are generally best for germination [68,181]. Sabo and others  found a constant temperature of 73 degrees Fahrenheit (23 Â°C), or alternating temperatures of 54 degrees Fahrenheit (12 Â°C) for 8 hours with 88 degrees Fahrenheit (31 Â°C) for 16 hours, gave best germination of sideoats grama. Over 1 month, germination of seed collected in southeastern Montana averaged 95% for treatments of 68 to 86 degrees Fahrenheit (20 to 30 Â°C). Seeds required 1 to 3 days to achieve 50% germination. Germination for the low-temperature treatment of 50 degrees Fahrenheit (10 Â°C) was only 60%, and seeds required 15 days to attain 50% germination . Jordan and Haferkamp  found the minimum germination temperature for the 'NM-28' cultivar was 48 degrees Fahrenheit (8.9 Â°C).
Planting depth also affects germination rate. Sideoats grama had the highest germination rate (58%) at 1-inch planting depth compared to 37% at 0.5 inch (12.7 mm), 10% at 2 inches, and 0% at 3 inches (76 mm) . Germination of sideoats grama is good under both dry and moist conditions . Germination of sideoats grama is "not greatly affected" by water stress down to 1 mP . Qi and Redmann , however, found sideoats grama had a lower tolerance to water stress than was reported in Sabo and others , with 1 of the lowest germination rates of the 6 grass species tested under water stress.
Seedling establishment/growth: Seedling vigor of sideoats grama is good to excellent [86,212]. In a study comparing seedling growth, sideoats grama seedlings developed more quickly than most of the 44 prairie forb and grass species tested . In the greenhouse, tillering began 3 weeks after seeds of sideoats grama were planted, and continued at a rapid rate . Nine-week-old plants produced 20 to 40 stems and rhizomes. Temperature affected seedling growth rate. Seedlings grew more rapidly at 80 to 85 degrees Fahrenheit (26.7 to 29.4 Â°C) than at 60 to 65 degrees Fahrenheit (15.5 to 18.3 Â°C) . Of 5 grass species tested for growth patterns, 'Coronado' sideoats grama showed the most rapid shoot and root growth .
Sideoats grama seedlings are more drought tolerant than many other warm-season grasses, although seedlings that are not well established can be killed by a short drought period . Dahl and others  found sideoats grama was 1 of the easiest species to establish in wet or dry years in Texas. Root length and root:shoot ratio are important factors in survival rates of seedlings growing in water-limited areas . In a study by Simanton and Jordan , sideoats grama had the highest root length, shoot length, and root:shoot ratio compared to other warm-season grass species. Robocker and others  reported sideoats grama has high root growth in relation to leaf development.
Asexual regeneration: Sideoats grama reproduces asexually from rhizomes and tillers. Rhizomes are the main form of reproduction in Bouteloua curtipendula var. curtipendula . The bunchgrass variety of sideoats grama (Bouteloua curtipendula var. caespitosa) reproduces asexually from tillers. Although rhizomatous, vegetative expansion of the 'El Reno' cultivar of sideoats grama studied in Colorado was primarily from tillering. Rhizomes did not contribute significantly to new shoot production. According to Sims and others  the 'El Reno' cultivar produced rhizomes mainly from reproductive shoots and tillers mainly from vegetative shoots.
Growth Form (according to Raunkiær Life-form classification)
More info for the terms: geophyte, hemicryptophyte
RAUNKIAER  LIFE FORM:
Life History and Behavior
More info for the terms: formation, natural, phenology, root crown, warm-season
Sideoats grama starts growth in mid-spring, and generally flowers between July and September . In native tallgrass prairie in central Oklahoma, anthesis occurs from July to September, seedlings sprout in November and December and in March and April, and seed formation and dissemination occur from July through November . The growing period for sideoats grama in the southern Great Plains is April through October . In Wisconsin, root crown growth occurred from early April through mid-July, then again from early to mid-August. Production of secondary and tertiary shoots occurred from mid-March through late October, and anthesis occurred from mid-July to mid-August . Production of shoots slowed during flower production but did not cease at any time during the growing season. In general, sideoats grama flowers from April to October . Flowering dates for sideoats grama vary with location, and are summarized in the following table:
|Location||Beginning of Flowering||End of flowering|
|IL, VA, WV, CO, WY||July||September [142,193,226]|
Phenology differs due to variety and place of origin. Olson  planted 4 cultivars of sideoats grama, and cultivars of other warm-season grasses, in a common garden in Minnesota to study phenology of grasses collected from locations throughout the Great Plains. Sideoats grams cultivars from North Dakota ('Kildeer') and South Dakota ('Pierre') reached anthesis 21 to 28 days earlier than cultivars from Kansas ('Butte' and 'Trailway'). In clones grown from locations throughout the Great Plains, flowering began earliest in plants from northern and western sites, and occurred progressively later in plants originating in more southward and eastward sites . Flowering for northern clones was in late June, with the earliest flowering in clones from northeastern Montana. A study by Olmsted  also provides insight on the phenological variability of sideoats grama from different locations. Olmsted tested the photoperiodic response of sideoats grama from Texas, Oklahoma, and North Dakota. He found the Texas strain grew and flowered vigorously in natural or simulated 13-hour daylight. The Oklahoma strain flowered equally well and rapidly with 13 to 14 hours of daylight, and the North Dakota strain grew and flowered vigorously in 14- and 15-hour photoperiods. The photoperiodic responses of the strains corresponded to flowering earlier in the year and during longer days for more northern species, which may have been an adaptation in response to northward expansion of sideoats grama in the past.
Molecular Biology and Genetics
Barcode data: Bouteloua curtipendula
Statistics of barcoding coverage: Bouteloua curtipendula
Public Records: 5
Specimens with Barcodes: 6
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: Widespread and common throughout much of North America.
Sideoats grama has a global rank of G5, indicating it is demonstrably secure globally, but may be quite rare in parts of its range . State and province protection status for sideoats grama is given below.
|Connecticut||Endangered||Species in danger of extinction throughout all or a significant portion of its range, and with less than 5 occurrences in the state .|
|Kentucky||Species of special concern||Taxon should be monitored because is exists in a limited geographical area; may become threatened or endangered due to habitat destruction or biological or other factors; or is thought to be rare or declining but insufficient evidence exists to list it as endangered or threatened .|
|Maryland||S2||State rare or vulnerable to extirpation. Typically 6 to 20 occurrences or few remaining individuals or acres .|
|Michigan||S1/S2||S1: Critically imperiled in the state because of extreme rarity (5 or fewer occurrences or very few remaining individuals or acres). S2: Imperiled in state because of rarity (6 to 20 occurrences or few remaining individuals or acres) or because of some factors making it very vulnerable to extirpation from the state .|
|Mississippi||S3/S4||S3: Rare or uncommon in state (21 to 100 occurrences). S4: Apparently secure in state .|
|New Jersey||Endangered||Species in danger of extinction throughout all or a significant portion of its range .|
|New York||S1, Endangered||Critically imperiled because of rarity ( 5 or fewer sites or very few remaining individuals) or extremely vulnerable to extirpation from the state due to biological factors .|
|Pennsylvania||S2||Imperiled in the state because of rarity or because of some factor(s) making it very vulnerable to extirpation from the state. Typically 6 to 20 occurrences .|
|West Virginia||S3||May be somewhat vulnerable to extirpation (20 to 100 documented occurrences) |
|Manitoba||S2||Rare and may be vulnerable to extirpation .|
Sideoats grama is the state grass of Texas .
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).
Comments: Some low-level threats from lack of disturbance/succession (glades may be fire-dependent) and from competition with exotics (Southern Appalachian Species Viability Project 2002).
Pests and potential problems
Grasshoppers can be destructive of seedling stands. Some stem and leaf rust occurs in wet years and Mankin (1969) found several leaf spot and root rot fungi occurred on side-oats grama.
Herbicides and fertilizer treatments:
Reaction of sideoats grama to
herbicide treatments varies with the herbicide and stage of phenological development. Sideoats grama had good to
excellent tolerance to imazethapyr
applied either pre- or postemergence . Application of 2,4-D favored establishment of sideoats grama
on an upland site seeded with native grasses and treated with 2,4-D, atrazine, and mowing
. In a study of the effects of clopyralid, picloram,
triclopyr, and 2,4,5-T, development of sideoats grama seedlings was reduced as
rate of herbicide application increased . Clopyralid had minimal effect at
application rates of 0.98 lb/ac (1.1kg/ha) and less, but the other 3 herbicides caused
more damage as application rate increased. Triclopyr and 2,4,5-T
had detrimental effects at 0.98 lb/ac (1.1kg/ha) or higher, and picloram caused increasingly
negative effects on growth at 1.96 lb/ac (2.2 kg/ha) and higher.
Application of fertilizer
may increase sideoats grama production. Application of nitrogen and nitrogen+phosphorus fertilizer increased
herbage production of sideoats grama
relative to the control on 3 different soil types in which laboratory
specimens were grown . On a loamy upland site in south-central New Mexico, cover of sideoats grama increased over
4 years with annual June application of nitrogen .
Light competition from trees may have detrimental effects on
sideoats grama stands. Sideoats grama increased after cabling of Colorado pinyon-oneseed
juniper woodland in south-central New Mexico . After trees, shrubs, and forbs in another pinyon-juniper
woodland were killed, herbage production for sideoats grama increased from 5 kg/ha 1 year after
treatment to 155 kg/ha 3 years after treatment . In eastern Nebraska native
little bluestem prairie, cover
of sideoats grama was lowest in shaded
plots under eastern redcedar, compared to plots
in open sites and at the edge of tree crowns . In contrast, McPherson and
Wright  found cover of sideoats grama increased
with increased canopy cover of redberry juniper on
both ungrazed and formerly grazed sites, even though overall grass production
decreased with greater canopy cover. In another study sideoats grama increased on plots where redberry
juniper was controlled with picloram .
Sideoats grama can reduce the success of other species. Sideoats grama in dense stands may reduce
honey mesquite (Prosopis glandulosa) seedling
establishment . Sideoats grama reduced dry mass of honey mesquite
when the 2 species were planted at the same time or when sideoats grama was already
established. Similarly, sideoats grama caused a decrease in the dry weight of
smooth hawthorn (Crataegus
laevigata) and sweet acacia (Acacia smallii) when planted with
those species .
Extracts from Utah juniper foliage and litter suppress growth of sideoats grama seedlings .
In grasslands, sideoats grama may be reduced by competition from taller prairie grasses more
adapted to mesic sites, declining in cover or disappearing from mesic
sites within a few years . Sideoats grama may have lower yield where planted with
tallgrass species, as taller grasses can outcompete sideoats grama .
Response to grazing pressure:
Sideoats grama is often considered an
increaser under grazing [6,90,113,162]; however, sideoats
grama often decreases under grazing on arid western ranges [20,24]. Tomanek and Albertson 
report sideoats grama both
decreased and increased under grazing, depending on site characteristics and
grazing pressure. Sideoats grama often increases under grazing in tallgrass
prairies [90,162]. When growing in association with little bluestem and blue
grama, sideoats grama often increases with
heavy grazing pressure but may be replaced
by blue grama or forbs . In Nebraska sideoats
grama increases under heavy grazing on favorable, wetter sites, but
does not do well under prolonged heavy grazing . Sideoats grama may increase under grazing due to
reduced competition by other
grasses. Percent species composition of sideoats grama declined from 11.54% to 1.12%
after 17 years of protection from grazing on a mixed-grass prairie in Nebraska
. On native prairie site in Kansas, a decrease in competition due to
drought caused an increase in relative cover and
seed production of sideoats grama until other grasses recovered . Sideoats
grama is most abundant on
steep slopes not easily accessible to cattle, and is increasing on some western
ranges protected from grazing [20,67]. Bolander  states sideoats grama
is common in areas of Arizona chaparral that have not been overgrazed, but is
replaced by other grasses in heavily grazed areas. Similarly, cover of sideoats grama in semiarid grasslands
of the Edwards Plateau in Texas has been
reduced by prolonged overgrazing .
Fire affects the response of sideoats grama to grazing. Sideoats grama increased in early spring-burned pastures
where fire essentially eliminated Kentucky bluegrass (Poa pratensis), increasing grazing
pressure on sideoats grama . Sideoats grama increased in cover and frequency in response to
bison grazing at stocking rates of 9 ha/AU to 5 ha/AU ; the difference between grazed and ungrazed plots was significant (p < 0.1) on
tallgrass prairie sites burned every 4 years but was not significant on plots
burned annually. On season-long grazed sites, moderately stocked (3.3 ac/head)
with cattle, sideoats grama represented a greater proportion of vegetation composition on
spring-burned plots than on unburned plots monitored from
1950 to 1967 . Sideoats grama significantly (p< 0.05) increased in percent
species composition 4 years after fire on sites under season-long
continuous grazing and fertilized with 80 lb/ac (90 kg/ha) nitrogen, but decreased
(though change not significant at p = 0.05) on unburned, grazed plots fertilized at 80 lb/ac nitrogen . For more information about the response of sideoats grama to
fire, see Fire Effects.
Several studies have investigated the effects of grazing and mowing on
sideoats grama [139,161,171]. Clipping reduces aboveground and belowground dry
mass , and can increase stands of sideoats grama if clipped herbage is
removed from the ground . Clipping sideoats grama at a high
frequency and a high intensity (to 3 inches (8 cm) every 3 weeks) severely reduced
plant vigor compared to lighter, less frequent clipping (to 6 inches (15 cm) every 6
weeks) . Reardon and others  caution against using clipping
as a direct surrogate for studying grazing response, reporting that regrowth
of sideoats grama was greater after grazing by domestic sheep, goats , or cattle than clipping to the
same height as grazed plants.
Cultivars, improved and selected materials (and area of origin)
Contact your local Natural Resources Conservation Service (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.”
‘Butte’ was selected at Nebraska AES, Lincoln, USDA-ARS and SCS cooperatively by E.C. Conard and L.C. Newell. It represents native collections from Holt and Platte Counties in Nebraska that were combined and tested as Nebraska 37. Repeated field plantings revealed superior germination and establishment characteristics when compared with other sources.
‘El Reno’ was released cooperatively in 1944 by the SCS, Manhattan, Kansas Plant Materials Center and Kansas AES. The original seed was collected in a field location near El Reno, Oklahoma in 1934. The material was outstanding for leafiness, forage production and vigor. It also ranked well for disease resistance, seed production, and winter hardiness. It is widely used in range seedings and is adapted to Kansas, Oklahoma and northern Texas.
‘Haskell’ was released in 1983 by the James E. “Bud” Smith Plant Materials Center, Texas AES and USDA-ARS. The seed for this release was originally collected in 1960 by J.C. Yeary, Jr. in Haskell, Texas.
It was selected based on rhizome production and adaptation as far south as the Rio Grande Valley in Texas. It is also known for its high forage palatability and prolific seed production.
Killdeer was informally released in the late 1960’s by the Bismarck Plant Materials Center in Bismarck, ND. It is composed of seed collected from native stands in 1956 near Bowman, Bowman County and Killdeer, Dunn County, North Dakota. Killdeer possesses outstanding vigor, leafiness, fair seed production, freedom from disease and persistence in a cold, semi-arid environment.
‘Niner’ was released in 1984 by SCS and the New Mexico and Colorado AES. The original seed for the release was collected by G.C. Niner and J.A. Anderson in 1957 west of Socorro, New Mexico. Niner was a bulk increase of the collection made by Niner and Anderson.
Pierre was informally released in 1961 by the Bismarck Plant Materials Center and the South Dakota AES. The original seed for the release was collected in 1954 in Stanley County west of Pierre, South Dakota. The release is described as outstanding in vigor, leafiness, freedom from disease, seedling vigor and persistence in a semi-arid environment.
‘Premier’ was released in 1960 cooperatively by Texas AES and USDA-ARS and NRCS. The original seed was collected in 1953 from a single plant growing between Cuauhtemoc and Chichuahua, Mexico. The release is described as having good seedling vigor, good seed yield, drought tolerance, upright growth form and leafiness.
‘Trailway’ was cooperatively released in 1958 by Nebraska AES and USDA-ARS. The original seed was collected in 1953 in northern Holt County by L.C. Newell. The release is described as winter hardy, long lived, late maturing with a somewhat indeterminate heading and flowering response. Requires most of the growing season to mature a crop in eastern Nebraska and may fail to produce seed in areas with a shorter growing season.
‘Vaughn’ was released in 1940 by the New Mexico AES and SCS Plant Science Division. The original seed was collected from native stands in 1935 near Vaughn, New Mexico. The release is described as slightly variable, but all have erect leaves, good seedling vigor and easy to establish.
Northern, Central and Southern Iowa Germplasms were released in 1995 as source identified releases, by the Elsberry Plant Materials Center, University of Northern Iowa, Iowa Department of Transportation, Iowa Crop Improvement Association and NRVC. They are all composite lines from collections made in Northern, Central and Southern Iowa.
Seed production experiments conducted in Nebraska in the 1950’s found that side-oats grama response to nitrogen fertilization was dependent on moisture conditions during critical growth periods (Newell et al., 1962). Seed yields measured as whole spikes were substantially increased over unfertilized check plots by all rates of nitrogen applied. Under drought conditions the application of 60 and 90 pounds of nitrogen yielded whole spike yields of approximately equal amounts. Under favorable moisture conditions nitrogen fertilization improved the quality of the caryopsis by increased weight per 1000 caryopsis over unfertilized plots.
Seed of side-oats grama normally found on the open market consists of either whole spikes or individual florets, or mixtures of these, which vary widely in their content of germinable caryopsis. Thus, seeding rates of side-oats must be computed on the basis of purity and viability of the seed lot. Purity analysis of side-oats can be complicated by the inclusion of adhering glumes and spike fragments as part of the seed unit. As long as the seed unit has a germinable caryopsis in the spike it is considered viable and used in the computation of pure live seed by the seed analyst. Thus a spike may contain several germinable caryopses, but is counted only as one for the purpose of germination percentage.
The effect of burning on seed yield was studied by Newell etal. (1962) in fertilized and unfertilized plots. Although the seed yield results were numerically larger from both levels of fertilized plots when burned, the differences could not be proven to be statistically different. This finding is noteworthy since it proves that proper burning, if not conducted too late in the spring, does not reduce seed yield. Burning is a proven method of cleaning the field for the new seed crop year. Burning has also been known to help control cool season weeds and reduce disease inoculums for the new crop.
Thus, side-oats grama may be grown for seed in cultivated rows, and will respond to timely fertilization and irrigation applications.
As a mid-grass, side-oats grama is intermediate in many respects between the tall and short grass species. Side-oats grama is not as resistant to grazing
pressure as is blue grama due to its taller growth habit. Side-oats seedlings are vigorous and stands tend to establish quickly and can often be utilized for forage production the second year after planting. Side-oats grama is usually included in range mixes and should be managed as native rangeland. Management should include proper livestock stocking rates and correct season of use.
Relevance to Humans and Ecosystems
Value for rehabilitation of disturbed sites
Sideoats grama establishes quickly and provides good erosion control . It is commonly seeded on southern plains ranges to reduce wind erosion, reduce soil temperatures and evaporation, and help control weeds . Sideoats grama is very drought resistant [3,113,153,213],. Density and vigor of sideoats grama stands may decrease during drought ; however, stand density may increase, and sideoats grama expand by self-seeding, after drought . Sideoats grama can increase rapidly on prairie damaged by extreme drought or overgrazing .
Seed weight and seeding rate: Seed weight for sideoats grama is 170,000 seeds/lb  to 191,000 seeds/lb [44,192]. Range of pure live seed (PLS) per pound of bulk seed was reported as 42,020 to 64,940 PLS/lb bulk . Recommended seeding rate is 3 to 6 lbs PLS/ac (3.3 to 6.7 kg/ha). Seeding dates vary from April 1 to May 15 in the northern and central Great Plains, January to April in the southern Great Plains and June 15 to July 15 for Trans-Pecos Texas and the Southwest .
Sideoats grama is often included in native seed mixes for prairie reclamation [5,78] and is widely used for reseeding ranges . Stubbendieck and others  recommend sideoats grama as a component of native grass mixes in silty, clayey, and sandy sites throughout Nebraska. Sideoats grama is used for revegetating coal surface-mined lands in the eastern United States , Iowa , eastern Montana , and other areas. It has been seeded successfully on iron ore for mine reclamation in Wisconsin .
Cultivars: Sideoats grama is commercially available . Several improved cultivars of sideoats grama have been developed including 'Vaughn' and 'Niner,' originating from western areas of the Southwest , 'Trailway' from Nebraska, 'Pierre' from South Dakota, 'Kildeer' from North Dakota, 'Premier' and 'Haskell' from Texas, as well as 'EL Reno,' 'Butte,' and 'Native' [97,156,186]. Production and timing of maturity of the individual cultivars vary by planting site . Improved cultivars are often used for reclamation. Of several cultivars evaluated at a mine site in the Southwest, 'Vaughn' ranked best for both stand density and vigor in all 3 study years, followed by 'NM-28' and 'El Reno' .
Importance to Livestock and Wildlife
Sideoats grama is highly productive, providing valuable forage for all classes of livestock and wildlife . It is good winter and summer forage . In some areas sideoats grama is an important summer food when cool-season grasses are dormant . In Arizona it maintains relatively high forage value throughout the year. It provides forage earlier in the spring than the other gramas, remains green later in the fall, and cures well .
Palatability/nutritional value: Sideoats grama is highly palatable and nutritious, and is readily eaten by all classes of livestock . Leaves are more palatable than stems and are generally consumed 1st . Sideoats grama is highly palatable to livestock during late spring and summer, and provides fair forage value when mature . It is highly palatable while green and is consumed throughout the growing season, including early spring (if spring rains occur) . In Nebraska it is grazed mostly in late summer and fall, and remains moderately palatable into winter .
The following table provides a summary of forage use of sideoats grama by livestock and wildlife:
|Livestock or wildlife species||Forage value and season of use||Location|
|Cattle||good||AZ, CO, MT, ND, OK, TX, WY [15,50,58,96]|
|Horses||good||CO, MT, ND, WY |
|Domestic goats||used||Mexico |
|Domestic sheep||good||CO, MT, ND, WY |
|Mule deer||relatively low use, March-July; light use all seasons||AZ, CO [8,110,116]|
|White-tailed deer||relatively low use; measured March-July||AZ |
|Pronghorn||good; used all seasons||TX |
|Small mammals||seeds and seedheads used||KS [63,157,186]|
|Songbirds||seeds and seedheads used||location not specified [157,186]|
Studies report varying results for the nutritional value of sideoats grama. Sideoats grama has fair energy value and fair protein value but poor food value for mule deer, white-tailed deer, and pronghorn in North Dakota . It is moderately valuable winter forage in the southern Great Plains, but nutrient value is too low to be one of the outstanding warm-season forage grasses in the region . Newell and Moline  reported sideoats grama provided high-quality forage from May through October, as indicated by crude protein content. However, according to a study in Texas, protein content was ranked "good" in samples taken in the early growth stage and "deficient" for mature growth. Protein was considered deficient in 60% of sideoats grama samples. Sideoats grama was "deficient" and "very deficient" for phosphoric acid in the young and mature growth stages, respectively . In samples from Arizona, crude protein content of sideoats grama varied seasonally from 2.66% to 6.23%, with the highest levels in May to June . Crude protein content was also highest in May and June in both standing biomass and 30-day-old regrowth for 'El Reno' sideoats grama from 3 sites in Texas. Crude protein content values for sideoats grama ranged from 1.9% to 13.2%, and varied among sites and seasons. In-vitro digestible organic matter was also generally highest in May and June at all 3 sites . Protein content of dormant sideoats grama from an arid New Mexico range was 3.7%. Sideoats grama was low in many other nutrients compared to other species . The table below summarizes nutritional content of sideoats grama forage, expressed as percentage of dry matter :
|Fresh, immature||Fresh, mid-bloom||Fresh, full bloom||Fresh, mature||Fresh, overripe||Fresh, early leaf (without lower stems)||Fresh, mid-bloom (w/o lower stems)||Fresh, dormant (w/o lower stems)|
|Domestic goats-dig. protein||7.4||4.4||3.2||0.9||-0.5||1.9||1.8||0.1|
|Domestic sheep-dig. protein||7.8||4.8||3.6||1.4||-0.1||2.3||2.2||0.5|
|Domestic rabbits--dig. protein||7.6||5.2||4.2||2.3||1.0||3.1||3.0||1.6|
On plots treated with annual spring burning and application of 2.2 kg/ha tebuthiuron, crude protein content and percent digestibility of sideoats grama increased from the 1st year of treatment to the 2nd year. Pretreatment data were limited, but showed lower nutritional value of grasses prior to treatment. For both years of treatment, crude protein and percent digestibility of sideoats grama were highest in May and declined steadily throughout the sampling season, to mid-September .
Sideoats grama is sometimes used for hay in southwestern and prairie states [15,105,193,201,225]. According to Williams , livestock eat the coarse leaves more readily dry than when leaves are fresh.
Cover value: Sideoats grama provides excellent nesting cover for a variety of songbirds and is readily used by a variety of small mammals . Sideoats grama is sometimes seeded for game bird habitat improvement, and is recommended in grass mixes to provide cover for nesting lesser prairie-chickens [151,184]. Sideoats grama provides good cover for quail species  and is sometimes planted for scaled quail habitat improvement . It is listed as a component of prime sharp-tailed grouse habitat . Sideoats grama provides good habitat for black-tailed jackrabbit and eastern cottontail on Kansas prairies . It is a component of open grasslands preferred by mountain sheep . In Arizona, areas used by mountain sheep had a significantly greater (p < 0.05) cover of sideoats grama, and a greater proportion of grass cover overall, than areas mountain sheep did not use.
Other uses and values
Forage: Side-oats grama produces high quality, nutritious forage that is relished by all classes of livestock throughout the summer and fall, and it remains moderately palatable into winter. This makes it one of the most important range grass species.
Erosion Control: Weaver and Albertson (1944) described the role of side-oats grama in the recovery of grasslands following the drought of the 1930’s. It was one of the few grasses that covered large areas bared by the loss of other grasses during the drought period. Side-oats grama is recommended in grass mixtures for range and pasture seeding, for earth fill and bank stabilization, for other critical areas and recreational plantings. Successful seeding can be obtained in rocky, stony or shallow soil sites. In fact side-oats is often found in nearly pure stands on caliche outcrops, stony hillsides and breaks (Harlan, 1954).
Wildlife: Side-oats provides some forage for antelope and deer when actively growing. Elk will use this grass as forage throughout the year. Leithead et al. (1971) indicated that the seed of this species was consumed by wild turkeys.
The Bouteloua curtipendula foliage is blue-green in color and the flowers are purple. The small oat-like seeds develop on the side of the stalk.
Sideoats grama is a warm-season grass, growing 30–100 cm (12-40 inches) tall, and grows well on mountainous plateaus, rocky slopes, and sandy plains. The grass is also drought- and cold-tolerant and is hardy in zones 4-9.
- Soule, J.A. 2012. Butterfly Gardening in Southern Arizona. Tierra del Soule Press, Tucson, AZ
Names and Taxonomy
(Michx.) Torr. (Poaceae) [49,73,78,91,104,105,128,217]. Recognized varieties are as follows
Bouteloua curtipendula var. caespitosa Gould & Kapadia
B. curtipendula var. curtipendula (Michx.) Torr.
Most sources reviewed in this species summary do not distinguish between varieties, but pertain to areas within
the range of Bouteloua curtipendula var. curtipendula
(see Distribution and Occurrence).
Where information presented in this summary pertains to a particular variety,
the variety will be specified as either B. curtipendula var. curtipendula
or B. curtipendula var. caespitosa.
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