This description provides characteristics that may be relevant to fire ecology, and is not meant for identification. Keys for identification are available (e.g., [27,37,47,48,49,61,62,63,78,79,80,90,99,108, 111,126,134,154,167,172,173,176]).
Woods strawberry is a low-growing, deciduous perennial herb [6,27,37,62,63,72,73,90,99,108,120,126,145,154, 173,175], with petioles and flowering stems typically arising from a single crown in rosette form. Occasionally a single crown may split into 2 or more crowns by the development of an axillary meristem, but production of leaves and flowers is generally restricted to a single meristematic axis in each ramet [6]. Petioles are generally 0.3 to 6.9 inches (0.8-17.5 cm) long [37,78,80,173], with flowering stems often shorter [72]. Leaves are basal and palmately trifoliate [37,62,63,72,78,79,80,90,99,108,120,141,145,154, 173,175], with leaflets 0.5 to 2.6 inches (1.3-6.5 cm) long and 0.5 to 2.8 inches (1.3- 7.0 cm) wide [37,78,108,145,173], the terminal leaflet being largest [37,173]. Flowers of Fragaria vesca ssp. vesca, F. v. ssp. americana, and F. v. ssp. californica are exclusively perfect, while F. v. ssp. bracteata produces occasional female-only plants [146]. Fleshy fruits are up to 0.4 inch (1 cm) thick and covered with 0.05 inch (1.3-1.4 mm) long achenes [37,62,78,80,108,126,173]. Crowns arise from short rhizomes [63,78,90,99,108,126], spreading and forming colonies by stolons that root and produce plantlets at the nodes [37,47,62,63,72,73,78,80,90,99,108,120,126,145, 154,173,175].
In the western United States, woods strawberry is distributed from Washington south to California, Arizona, New Mexico [28,37,59,72,78,90,108,157,173,175], and the Guadalupe Mountains of western Texas [37,86]; and east through the Rocky Mountain region [23,37,38,49,62,81,99,171,172,173] and the Black Hills [47,95,162]. Cronquist and others [37] suggest that woods strawberry is "seemingly absent from the western ¾ of the Great Basin", despite indications that its occurrence has been recorded in Nevada [37,81]. It occurs somewhat infrequently in the northern Great Plains, south to Nebraska [63,74]. In the eastern United States, woods strawberry is distributed from the Lake States east to coastal New England, and south to Missouri, Tennessee, and North Carolina [6,61,63,65,111,126,134,141,155,176]. Kartesz and Meacham [89] indicate the possibility that it also occurs in Mississippi. Woods strawberry is introduced in Hawaii [8]. Plants Database provides state distribution maps for woods strawberry and its infrataxa.
In Canada, woods strawberry occurs from coastal British Columbia east to Newfoundland [37,61,72,79,80,90,107,125,134,134,173], as well as in Northwest Territories [89]. It also occurs in Baja California, Mexico [37,78,108,175].
Globally, woods strawberry distribution is circumboreal [98,99]. While it is widely considered a native species in North America, at least some populations may originate from introduced European stock [61,111,141], especially in the northeastern United States and adjacent Canada [61,80,134,141], and the northern Great Plains [63].
Comprehensive surveys examining the presence or absence of woods strawberry within the following biogeographic vegetation schemes are not available. These lists represent a "best estimate" of woods strawberry occurrence based on information obtained from floras and other literature, herbarium samples, and confirmed observations.
Fire adaptations: Several sources indicate that woods strawberry is adapted to survive low- to moderate-severity fires via subsurface perennating buds. Powell [124] suggested that woods strawberry survives "cool" fires via stolons that are sequestered in unburned litter and duff layers. Brown and Debyle [29] considered woods strawberry a fire endurer, which Rowe [136] classed as those plants able to resprout after the passage of fire. Wang and Kimball [170] included woods strawberry in the POSTFIRE REGENERATION STRATEGY class sprouter (regenerated from surface or buried buds) following a wildfire in a southeastern Manitoba boreal mixedwood forest.
There is also some suggestion that, at least at the population level, woods strawberry is adapted to fire-prone habitats due to a propensity for postfire seedling establishment. In a study of postfire plant cover in northeastern Oregon, Johnson [85] indicated that in postfire year 5, woods strawberry established by seed dispersed from outside the measurement plots in a grand fir-pinegrass habitat type. Suggestions that woods strawberry seedling establishment is generally benefited by some type of disturbance (see Seedling Establishment and Growth and Successional Status) also supports the hypothesis that woods strawberry seedling establishment is promoted by fire. In addition, Strickler and Edgerton [156] suggested that heat may promote woods strawberry seed germination, but a small sample size provided limited experimental evidence.
Although several sources have suggested that seedling establishment and vegetative spread typically do not occur together concurrently, at least within established populations (see Seedling Establishment and Growth), Ahlgren [3,4] observed both woods strawberry seedling establishment and vegetative sprouting, in about equal numbers, in postfire experiment plots in northeastern Minnesota.
FIRE REGIMES: As of this writing (2007), there is little published information linking woods strawberry with specific FIRE REGIMES. To the extent that woods strawberry benefits from fire (see Fire Effects), and to the extent that other postfire site characteristics are suitable for its occurrence, it is reasonable to suggest that woods strawberry is likely to be found in areas that experience moderately frequent, relatively low-severity fires. For example, Atzet and McCrimmon [15] described the fire regime of an Oregon white oak/woods strawberry habitat type in the southern Oregon Cascades as follows: "Fire occurred on three of the four sites sampled. Frequency is high, intensity is low, and many fires are confined to the type, without entering adjacent dense forest sites. Spread rates are moderated by the gentle topography. Heavy fuel production is low, but flashy fuels (grasses) are abundant and dry early in the summer. Vertical and horizontal fuel distribution is discontinuous and varied. Surface area, except for the grasses, is low" [15].
This is not to suggest that woods strawberry does not occur in areas with starkly different FIRE REGIMES than described above. For instance, it may be found in plant communities and ecosystems where the predominant disturbance type is something other than fire, such as windthrow, that may nevertheless benefit woods strawberry (see Successional Status). Given its apparent ubiquity across North America (see Distribution and Occurrence), fire regime is likely just one of many factors influencing woods strawberry occurrence and abundance.
The following table provides fire return intervals for plant communities and ecosystems where woods strawberry likely occurs (although precise distribution information is limited). Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) silver fir-Douglas-fir Abies amabilis-Pseudotsuga menziesii var. menziesii >200 grand fir Abies grandis 35-200 [11] maple-beech Acer-Fagus spp. 684-1,385 [34,168] maple-beech-birch Acer-Fagus-Betula spp. >1,000 silver maple-American elm Acer saccharinum-Ulmus americana <5 to 200 sugar maple Acer saccharum >1,000 sugar maple-basswood Acer saccharum-Tilia americana >1,000 [168] birch Betula spp. 80-230 [160] California montane chaparral Ceanothus and/or Arctostaphylos spp. 50-100 [121] sugarberry-America elm-green ash Celtis laevigata-Ulmus americana-Fraxinus pennsylvanica <35 to 200 [168] mountain-mahogany-Gambel oak scrub Cercocarpus ledifolius-Quercus gambelii 121] Atlantic white-cedar Chamaecyparis thyoides 35 to >200 beech-sugar maple Fagus spp.-Acer saccharum >1,000 black ash Fraxinus nigra 168] green ash Fraxinus pennsylvanica <35 to >300 [52,168] western juniper Juniperus occidentalis 20-70 Rocky Mountain juniper Juniperus scopulorum <35 [121] cedar glades Juniperus virginiana 3-22 [68,121] tamarack Larix laricina 35-200 [121] western larch Larix occidentalis 25-350 [12,18,42] yellow-poplar Liriodendron tulipifera <35 [168] Great Lakes spruce-fir Picea-Abies spp. 35 to >200 northeastern spruce-fir Picea-Abies spp. 35-200 [50] Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to >200 [11] black spruce Picea mariana 35-200 conifer bog* Picea mariana-Larix laricina 35-200 [50] blue spruce* Picea pungens 35-200 [11] red spruce* Picea rubens 35-200 [50] Rocky Mountain bristlecone pine P. aristata 9-55 [45,46] whitebark pine* Pinus albicaulis 50-200 [1,9] jack pine Pinus banksiana 34,50] Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-340 [17,18,161] Sierra lodgepole pine* Pinus contorta var. murrayana 35-200 [11] shortleaf pine Pinus echinata 2-15 shortleaf pine-oak Pinus echinata-Quercus spp. <10 [168] Jeffrey pine Pinus jeffreyi 5-30 western white pine* Pinus monticola 50-200 Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47 [11] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [11,16,101] Arizona pine Pinus ponderosa var. arizonica 2-15 [16,35,140] red pine (Great Lakes region) Pinus resinosa 3-18 (x=3-10) [33,58] red-white pine* (Great Lakes region) Pinus resinosa-P. strobus 3-200 [34,75,106] pitch pine Pinus rigida 6-25 [30,76] eastern white pine Pinus strobus 35-200 eastern white pine-eastern hemlock Pinus strobus-Tsuga canadensis 35-200 eastern white pine-northern red oak-red maple Pinus strobus-Quercus rubra-Acer rubrum 35-200 loblolly pine Pinus taeda 3-8 loblolly-shortleaf pine Pinus taeda-P. echinata 10 to <35 Virginia pine Pinus virginiana 10 to <35 Virginia pine-oak Pinus virginiana-Quercus spp. 10 to <35 sycamore-sweetgum-American elm Platanus occidentalis-Liquidambar styraciflua-Ulmus americana <35 to 200 [168] eastern cottonwood Populus deltoides <35 to 200 [121] aspen-birch Populus tremuloides-Betula papyrifera 35-200 [50,168] quaking aspen (west of the Great Plains) Populus tremuloides 7-120 [11,66,110] black cherry-sugar maple Prunus serotina-Acer saccharum >1,000 [168] mountain grasslands Pseudoroegneria spicata 3-40 (x=10) [10,11] Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [11,13,14] coastal Douglas-fir* Pseudotsuga menziesii var. menziesii 40-240 [11,112,131] California mixed evergreen Pseudotsuga menziesii var. menziesii-Lithocarpus densiflorus-Arbutus menziesii <35 California oakwoods Quercus spp. <35 [11] oak-hickory Quercus-Carya spp. <35 northeastern oak-pine Quercus-Pinus spp. 10 to <35 white oak-black oak-northern red oak Quercus alba-Q. velutina-Q. rubra <35 [168] canyon live oak Quercus chrysolepis <35 to 200 blue oak-foothills pine Quercus douglasii-P. sabiniana 11] northern pin oak Quercus ellipsoidalis <35 [168] Oregon white oak Quercus garryana <35 [11] bear oak Quercus ilicifolia <35 [168] California black oak Quercus kelloggii 5-30 [121] bur oak Quercus macrocarpa <10 [168] oak savanna Quercus macrocarpa/Andropogon gerardii-Schizachyrium scoparium 2-14 [121,168] chestnut oak Quercus prinus 3-8 northern red oak Quercus rubra 10 to <35 post oak-blackjack oak Quercus stellata-Q. marilandica <10 black oak Quercus velutina <35 [168] redwood Sequoia sempervirens 5-200 [11,56,158] western redcedar-western hemlock Thuja plicata-Tsuga heterophylla >200 [11] eastern hemlock-yellow birch Tsuga canadensis-Betula alleghaniensis 100-240 [160,168] eastern hemlock-white pine Tsuga canadensis-Pinus strobus x=47 [34] western hemlock-Sitka spruce Tsuga heterophylla-Picea sitchensis >200 mountain hemlock* Tsuga mertensiana 35 to >200 [11] *fire return interval varies widely; trends in variation are noted in the species reviewAs of this writing (2007) there is little published information specifically concerning the simultaneous management of woods strawberry and fire. It should be noted that woods strawberry occurs within a variety of plant communities and ecosystems that represent many types of FIRE REGIMES.
It has been suggested that woods strawberry might be an important species for mitigating postfire erosion potential. From observations of postfire shrubfields in northern Idaho, Hooker and Tisdale [82] wrote that woods strawberry "appeared to have an important stabilizing influence on the surface soils of the steeper slopes, since it was abundant after burning and sent out numerous stolons."
Habitat: Woods strawberry occupies a variety of habitats throughout its range. In the eastern United States and Canada, it commonly occurs in forest or woodland habitats (e.g. [6,51,111,141,154,167]). In the southeastern United States woods strawberry may be largely restricted to the rich, moist forests of the mountains [126,176]. Further north, there are also accounts of its occurrence in more open habitats such as old fields, meadows and grasslands [25,36,116,154]. In the northern Great Plains, woods strawberry is associated with woodland and riparian habitats [63,74].
In western North America, woods strawberry also commonly occurs in, but is not always restricted to, wooded or forested habitats. Although comprehensive surveys are lacking, it appears that woods strawberry can be found in all but the driest forest types in the western United States. Woods strawberry occurrence in forested habitats in this region is often associated with relatively recent disturbance. Examples include forest openings [27,62,72,122], roadsides [71,105], and recently cleared or early successional forest [105] (also see Successional Status below). Woods strawberry occurrence in western North America is also documented in meadows [47,48,49,79,108], open slopes [73,108], prairie-woodland mosaics [57], forest margins [99], and margins of meadows [127]. Reed [129] mentions woods strawberry occurrence in big sagebrush (Artemisia tridentata) habitats in Jackson Hole, Wyoming, although to date (2007) this is the only example encountered for this habitat.
Elevation: In mountainous western North America, woods strawberry occurrence has been reported from a wide range of elevations. Examples of such reports include: "low" to subalpine along the Pacific Northwest coast [122], "low to middle elevations" in Glacier National Park [145], and valley bottom to lower subalpine in west-central Montana [98]. Knight and others [93] indicated that woods strawberry's preferred habitat in the Medicine Bow Mountains of northern Colorado/southern Wyoming is "higher elevation, mesic sites."
The following table lists published accounts of elevation ranges where woods strawberry occurs in western North America. These examples are not necessarily elevational limits to woods strawberry distribution, but rather a range of elevations, particularly upper elevations, where woods strawberry might occur.
Location Elevation east-central and southeastern Arizona 7,000 to 9,500 feet (2,100-2,900 m) [90] southeastern Arizona >9,200 feet (2,800 m) [157] southern Arizona 7,900 to 8,000 feet (2,400 m) [28] California 100 to 6,500 feet (30-2,000 m) [78] Sierra Nevada Range, California <6,000 feet (1,800 m) [137] Colorado 5,000 to 9,500 feet (1,500-2,900 m) [73] near Crested Butte, Colorado 8,500 to 12,500 feet (2,600-3,800 m) [100] west-central Idaho 5,000 to 7,800 feet (1,500-2,400 m) [23] New Mexico 6,500 to 10,000 feet (2,000-3,000 m) [108] Utah 6,000 to 10,500 feet (1,800-3,200 m) [173] Uinta Basin, Utah 7,000 to 10,500 feet (2,100-3,200 m) [62] Cascade and Olympic Mountains, Washington up to 4,000 feet (1,200 m) [79,80] northwestern Wyoming 7,900 feet (2,400 m) [20] Intermountain West 5,900 to 7,900 feet (1800-2400 m) [37] Yellowstone National Park 6,000 to 7,600 feet (1,800-2,300 m) [44] Baja California "higher foothills to about" 8,200 feet (2,500 m) [175]The following table provides woods strawberry distribution data by elevation in the Siskiyou Mountains of Oregon and California, and is adapted from [174].
Elevation range (feet) 1,500-2,500 2,500-3,500 3,500-4,500 4,500-5,500 5,500-6,300 6,300-7,000 Percent frequency of occurrence 0.6 1.1 5.9 10.2 7.0 4.5As of this writing (2007) there is no published information regarding elevation and woods strawberry distribution in eastern North America.
Moisture: Based on general information contained in site descriptions, habitat types, etc., it appears that woods strawberry occurs under a wide range of moisture conditions, although it is probably not tolerant of extremely wet or dry conditions. Although comprehensive, rangewide information about moisture conditions for woods strawberry habitat is lacking, the following descriptions provide some guidelines, at least for parts of the western United States. Lackschewitz [98] indicated that woods strawberry occurs on sites in west-central Montana that are mesic (adequate moisture during all or most of the growing season, but rarely if ever flooded) to meso-xeric (moisture abundant in the early growing season but dry later on). Franklin and Dyrness [57] indicated that woods strawberry is more common in warm, dry forests, less common in cool, moist forests, and rare to nonexistent in cold, moist forests of the South Umpqua River valley, western Oregon.
Several native ungulates are known to graze woods strawberry foliage. Elk utilize it as summer forage in central Washington [26] and spring forage in northern Idaho [103]. Campbell and Johnson [31] provided evidence for year-round mountain goat and mule deer grazing on wild strawberries in north-central Washington. Woods strawberry was consumed by white-tailed deer in grand fir/queencup beadlily (Clintonia uniflora) and western redcedar/queencup beadlily habitat types in northern Idaho [92].
Tame mule deer utilized woods strawberry in Utah and Colorado. In a lodgepole pine-dominated forest area in northeastern Utah, woods strawberry constituted 5% by weight of the summer diet of tame mule deer in clearcut forest and mature forest habitats [43]. Tame mule deer utilized small amounts of woods strawberry in lodgepole pine and Englemann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) habitats in central Colorado in summer [169]. In an experiment on a central Colorado ponderosa pine/bunchgrass range, observations of grazing preferences of tame mule deer indicated that woods strawberry was among preferred food species. Average percent of mule deer diet comprised of woods strawberry was as follows [40]:
Average monthly use April May June July August October 3.8% 0% 0.8% 4.0% 6.5% 6.1% 5.5%Woods strawberry is also eaten by other native mammals, including grizzly bears [41], black bears [150,151], and raccoons [132], although it is unclear if these animals are eating strictly fruit, or if they are also utilizing foliage.
Fruits are eaten by grouse and songbirds [83,150,151]. Wild strawberry is "perhaps the most important herbaceous food plant for" ruffed grouse in Minnesota [67]. Hungerford [83] suggested that it was an important food for ruffed grouse in Idaho.
Palatability/nutritional value: According to Steele and Geier-Hayes [150,151] woods strawberry is moderately palatable to deer, elk and sheep. Its leaves remain "green through the winter" and provide a higher forage value "than most herb layer species during that season."
Cover value: No information is available on this topic.
Vegetation classifications describing plant communities where woods strawberry is a dominant species include:
Colorado:
New Mexico:
Oregon:
South Dakota:
Published information provides conflicting evidence concerning woods strawberry grazing tolerance. Hall [70]
reported that wild strawberries tended to increase with overgrazing in the Blue Mountains of eastern Oregon
and southeastern Washington. Steele and Geier-Hayes [147,148,149] indicated that, on "cutover" sites
in grand fir- and Douglas-fir-dominated habitat types in Idaho, woods strawberry was less tolerant of heavy
grazing than either Virginia strawberry or other common grazing-tolerant forbs. It was also suggested that
woods strawberry is susceptible to trampling from heavy livestock traffic [147,148,149]. In northern California,
Saenz [138] recorded the presence of woods strawberry in "lightly" grazed (only grazed "late in
the season" by cattle) Oregon white oak woodland, but it was not observed in "heavily" grazed
(grazed by cattle "for as much of the year as weather permitted") woodland, nor in "lightly"
grazed or "heavily" grazed grassland.
In meadow habitat surrounded by ponderosa pine (Pinus ponderosa) forest on the Mogollon Rim, northern
Arizona, exclusion of grazing by cattle, elk and deer had no consistent effect on relative abundance of woods
strawberry. Comparisons were made between grazed plots and fenced exclosure plots where there had been no
grazing for 8 to 9 years. Woods strawberry "relative abundance (%)" ranged from 0 to 6.5%, with no
discernable effect of grazing among 3 sites.
A study on the Rogue River National Forest, Oregon, suggests that on logged sites where woods strawberry is
present, removing slash (in this case piling and burning) results in greater woods strawberry presence,
compared with leaving slash in place [109].
The following table lists some examples of woods strawberry flowering phenology from throughout North America:
Reported dates for ripe fruits include mid-June to early August near Moscow, Idaho [83], and by early July in central New York [6]. Stolon production occurs from early June to late August in central New York [6] and early May through August near Ithaca, New York [88]. Stolon decay begins in late summer and connection between nodes is usually lost by spring, at least in central New York [6].
Leaf production occurs continuously from April to October in central New York, and a few leaves may overwinter [6]. Steele and Geier-Hayes [150,151] also reported that at least some woods strawberry leaves remain green through the winter in Idaho.
Schmidt and Lotan [139] reported the following phenological data for woods strawberry from locations east of the Continental Divide in Montana and in Yellowstone National Park, 1928-1937:
First appearance Leaves full grown Flowers start Flowers end Fruits ripe Seed fall starts Leaves start to color Leaves fallen Average date 5/7 6/8 6/10 7/5 8/3 8/12 8/29 9/24 Earliest date 4/20 5/10 5/10 6/29 7/21 8/1 8/5 9/1 Latest date 5/17 7/22 6/24 7/16 8/15 8/25 9/16 10/16Several studies have demonstrated an increase in woods strawberry populations following fire (see Discussion and Qualification of Plant Response below). Although published accounts indicate that, in general, woods strawberry populations increase following disturbance, including fire, to date (2007) there are no studies that explicitly compare the importance of vegetative spread with seedling establishment in postdisturbance population growth (see Successional Status). Ahlgren [3,4] observed both woods strawberry seedling establishment and vegetative sprouting, in about equal numbers, in postfire experiment plots in northeastern Minnesota.
To the extent that woods strawberry plants can survive fire, or that seedlings can establish in the postfire environment, it is apparent that fire can have a positive effect on woods strawberry populations. A review by Patterson and others [120] indicated that it regenerates from stolons following fire, reaching preburn levels within 3 to 7 years. Using the nomenclature of Volland and Dell [166], Powell [124] rated woods strawberry postfire response as medium, suggesting it will regain its preburn frequency or cover in 5 to 10 years.
Woods strawberry regenerates vegetatively and by seeds, although apparently the "predominant reproductive mode" is vegetative (Tamm 1948, as cited in [22]).
Pollination: According to Ostler and Harper [119], woods strawberry is "animal-pollinated", and flower structure is open with "unrestricted access to nectaries and/or pollen."
Breeding system: Fragaria vesca. ssp. vesca, F. v. ssp. americana, and F. v. ssp. californica have perfect flowers. Fragaria vesca ssp. bracteata is gynodioecious, in which most plants have perfect flowers, but occasionally some plants bear only female flowers [146].
Seed production: No information is available on this topic.
Seed dispersal: Seeds are probably dispersed by birds and mammals (Martin and others 1951, as cited in [3]), [148].
Seed banking: Although information describing longevity of viable, soil-stored woods strawberry seed is sparse, there is some indication that it does develop seed banks ([53] and references contained therein). Laboratory and field research in Europe indicate that viable woods strawberry seeds may persist in soil for at least 5 years [164].
It appears that the woods strawberry seed bank is found close to the soil surface. Kramer and Johnson [94] studied seed banks in Douglas-fir and grand fir forests in west-central Idaho. A total of 19 viable woods strawberry seeds were collected from 12 of 48 stands sampled. Ninety-five percent of viable woods strawberry seeds were found in the 0 to 2 inch (0-5 cm) depth, which was mainly composed of compacted litter and organic layers. Five percent of viable woods strawberry seeds were found in the 2 to 4 inch (5-10 cm) depth, which was predominantly mineral soil [94]. Similarly, of soil samples taken from 3 grand fir-dominated sites in the Blue Mountains of eastern Oregon, 2 sites yielded germinable seeds only from the litter/humus layer, and 1 site only from the 0 to 0.8 inch (0-2 cm) mineral soil layer. No woods strawberry seedlings emerged from the 0.8 to 1.6 inch (2-4 cm) soil samples [156].
Germination: As of this writing (2007) there is little published information describing conditions either favoring or inhibiting woods strawberry seed germination. Steele and Geier-Hayes [151] wrote that woods strawberry "germinates on moist mineral soil in partial shade."
Results from a laboratory experiment suggest that cold stratification may induce more rapid germination of woods strawberry seed but provides a much smaller, perhaps negligible effect on eventual numbers of germinants. Woods strawberry seeds were planted in sterilized soil and overwintered in either a coldframe or a heated greenhouse. Seeds overwintered in coldframes were brought indoors after 83 days and had greater germination (45.5%) compared with seeds from the heated greenhouse (32%). Seeds in the cold frame treatment also germinated more rapidly, between 14 and 56 days, while those in the heated greenhouse required between 48 and 252 days for germination [115].
Seedling establishment/growth: To date (2007), not much information has been published about woods strawberry seedling establishment and growth. However, there is some indication that seedling establishment occurs mainly apart from established populations, perhaps following some type of soil disturbance. A review by Eriksson [53] suggests that seedling establishment in preestablished populations of adult woods strawberry clones is rare, and that seedlings mainly contribute to establishment of new populations apart from established clones. Anecdotal evidence provided by Jurik [88] concurs, noting not only that seedlings do not seem to establish in preexisting populations, but that seedlings were observed only where the original vegetation was removed and mineral soil exposed. Steele and Geier-Hayes [148,150,151] noted that woods strawberry seedling establishment apparently requires bare shaded soil.
Asexual regeneration: Vegetative spread in woods strawberry occurs in 3 ways; although, according to a review by Eriksson [53], woods strawberry vegetative spread is mainly by stolons. Crowns arise from short rhizomes [63,78,90,99,108,126], and stolons arise from axillary buds, with individual ramets producing 1 to 4 stolons per season. Stolons may branch at alternate nodes. The nonbranching nodes produce 1 to 2 small leaves and adventitious root primordia, and will root when contacting moist substratum. Stolons decay over winter. Individual nodes may root up to 3.3 feet (1 m) from the parent ramet. Adventitious roots may also develop in the axils of decayed leaves allowing plants to "creep along the forest floor . . . through the accumulation of several years' decaying leaf bases" [6].
Although evidence is limited, it appears that woods strawberry is most prevalent in early successional forests in the western United States. Nevertheless, it also appears that it may be found in most, if not all, successional stages of forest development, at least within some western forest types. For example, Antos and Habeck [7] sampled vegetation in grand fir-dominated communities in the Swan Valley, western Montana. Average woods strawberry percent occurrence was significantly (P<0.05) greater in stands less than 90 years old (67%), compared with stands greater than 150 years old (7%) [7]. Habeck [69] also studied succession in western redcedar (Thuja plicata)-western hemlock (Tsuga heterophylla) zone forest communities in Glacier National Park. Woods strawberry exhibited its greatest presence in the earliest stages of succession in this zone, where forests that had established following fire were dominated by Rocky Mountain lodgepole pine (Pinus contorta var. latifolia) and, to a lesser extent, western larch (Larix occidentalis). Woods strawberry diminished in importance in later-successional communities where western redcedar and western hemlock were dominant [69]. Spies [144] found that mean woods strawberry percent frequency of occurrence in the Oregon Cascades was significantly (P<0.05) lower in old-growth (mean age = 395 years) forest stands, compared with mature (mean age = 115 years) or young (mean age = 60 years) stands. However, Steele and Geier-Hayes [147,148,149,150,151,152] characterized woods strawberry as a midseral species in several Douglas-fir- and grand fir-dominated habitat types in Idaho, and Ross and Hunter [135] included woods strawberry among "dominants in the climax vegetation" of the western redcedar-western hemlock association in Montana.
Several sources suggest or demonstrate that woods strawberry presence in western forest habitats is enhanced by disturbance. Hall [70] indicated that wild strawberries tend to increase with site disturbance in the Blue Mountains of eastern Oregon and southeastern Washington. Ferguson and others [55] indicated that woods strawberry increased substantially in response to both partial and total overstory removal in grand fir-dominated sites in northern Idaho and southeastern Oregon. Green and Jensen [64] noted that stands of grand fir (grand fir/wild ginger (Asarum caudatum) habitat type) that were subjected to clearcutting, broadcast burning, and high-intensity mechanical scarification resulted in a woods strawberry-thistle (Cirsium spp.) successional community. Nelson and Halpern [114] studied the responses of understory plants to aggregated retention harvests in 70 to 80-year-old and 110 to 140-year-old Douglas-fir-dominated forests on the western slope of the Cascade Range, southwestern Washington. Aggregates were 2.5 acres (1 ha), with 5 aggregates retained per 32-acre (13 ha) harvest unit. Sampling did not detect woods strawberry in preharvest plots of either the harvested or retention treatments, nor in postharvest retention units 1 to 2 years after cutting. However, woods strawberry was sampled at 3% frequency in harvested areas, with mean cover less than 0.05% [114]. A thinning experiment in a central Colorado Rocky Mountain lodgepole pine forest showed that woods strawberry cover was significantly (P<0.05) greater 5 years after heavy thinning (average basal area 30 ft²/acre), compared with moderate thinning (58 ft²/acre), light thinning (73 ft²/acre), and unthinned controls (basal area not reported) [39].
It is not clear if observed increases in woods strawberry associated with site disturbance are due to seedling establishment that is promoted by litter layer and soil disturbance (see Seedling Establishment/Growth). It is also possible that extant woods strawberry populations are released from competition for light by disturbance-induced changes in canopy structure, and expand their coverage by vegetative spread (see Asexual Regeneration). Although Kemball and others [91] considered woods strawberry to be shade intolerant, Steele and Geier-Hayes [149] indicated that woods strawberry is more shade tolerant than many of the early seral herb-layer species with which it is often associated in Idaho forests, and that it, along with Virginia strawberry, achieves its greatest coverage "beneath a light canopy of trees or tall shrubs where partial shade has reduced competition from earlier successional herbs" [147].
The scientific name of woods strawberry is Fragaria vesca L. (Rosaceae)
[27,37,47,48,49,51,61,62,63,78,79,80,89,102,111,126,133,155,162,167,173,176]. The following subspecies are
also recognized:
Fragaria vesca ssp. americana (Porter) Staudt [89,167,176]
Fragaria vesca ssp. bracteata (Heller) Staudt [28,87,89,123,171,172]
Fragaria vesca ssp. californica [78,89]
Fragaria vesca ssp. vesca [89]
According to Cronquist and others [37], woods strawberry and Virginia strawberry (Fragaria virginiana)
do not hybridize in the western U.S., and any similarities in diagnostic traits are more likely attributable
to variability within species.
For the purposes of this review, the common name "woods strawberry" is used when discussing
characteristics common to (or assumed to be common to) the species in general. When referring to infrataxa,
the scientific names for the subspecies listed above are used. When referring to multiple Fragaria spp.,
the name "wild strawberries" is used.
Fragaria vesca, commonly called the wild strawberry, woodland strawberry, Alpine strawberry, Carpathian strawberry or European strawberry, is a perennial herbaceous plant in the rose family that grows naturally throughout much of the Northern Hemisphere, and that produces edible fruits.[2][3]
The Latin specific epithet vesca means "thin, feeble".[4]
Five to eleven soft, hairy white flowers are borne on a green, soft fresh-hairy 3–15 centimetres (1–6 in) stalk that usually lifts them above the leaves. The light-green leaves are trifoliate (in threes) with toothed margins. The plant spreads mostly by means of runners (stolons), but the seeds are viable and establish new populations.[5][6][7]
Vilmorin-Andrieux (1885) makes a distinction between wild or wood strawberries (Fragaria vesca) and alpine strawberries (Fragaria alpina),[8] a distinction which is not made by most seed companies or nurseries, which usually sell Fragaria vesca as "alpine strawberry".
Under wild or wood strawberry, Vilmorin says:
It has seldom been seen in gardens since the introduction of the Red Alpine Strawberry. ... Wood Strawberry possesses a quite particular perfume and delicacy of flavour. 2,500 seeds to the gramme.
Under alpine strawberry, Vilmorin says:
A very different plant to the Wood Strawberry, and distinguished by the greater size of all its parts — the fruit in particular — and especially by the property (which is particular to it) of producing flowers and fruit continuously all through the summer. ... The fruit has nearly the same appearance and flavour as that of the Wood Strawberry, but is generally larger, longer, and more pointed in shape. The seed is also perceptibly larger and longer. A gramme contains only about 1,500 seeds.
As of November 2020, Plants of the World Online accepts two subspecies in addition to the autonym, Fragaria vesca ssp. vesca:[1]
Typical habitat is along trails and roadsides, embankments, hillsides, stone- and gravel-laid paths and roads, meadows, young woodlands, sparse forest, woodland edges, and clearings. Often plants can be found where they do not get sufficient light to form fruit. In the southern part of its range, it can grow only in shady areas; further north it tolerates more sun.[9] It is tolerant of a variety of moisture levels (except very wet or dry conditions).[9] It can survive mild fires and/or establish itself after fires.[9]
Although F. vesca primarily propagates via runners, viable seeds are also found in soil seed banks and seem to germinate when the soil is disturbed (away from existing populations of F. vesca).[9]
Its leaves serve as significant food source for a variety of ungulates, such as mule deer and elk, and the fruit are eaten by a variety of mammals and birds that also help to distribute the seeds in their droppings.[9]
It is a larval host to the two-banded checkered skipper.[10]
The wild strawberry is used as an indicator plant for diseases that affect the garden strawberry. It is also used as a genetic model plant for garden strawberry and the family Rosaceae in general, due to its:
The genome of F. vesca was sequenced in 2010,[11] and with greater detail and accuracy in 2017 by the Knapp UC Davis program.[12]
All strawberry (Fragaria) species have a base haploid count of seven chromosomes; Fragaria vesca is diploid, having two pairs of these chromosomes for a total of 14.
Evidence from archaeological excavations suggests that Fragaria vesca has been consumed by humans since the Stone Age.[13]
Woodland strawberry fruit is strongly flavored, and is still collected and grown for domestic use and on a small scale commercially for the use of gourmets and as an ingredient for commercial jam, sauces, liqueurs, cosmetics and alternative medicine. In Turkey, hundreds of tons of wild fruit are harvested annually, mainly for export.[14]
Most of the cultivated varieties have a long flowering period (and have been considered by botanists as belonging to Fragaria vesca var. vesca ssp. semperflorens). They are usually called alpine strawberries. They either form runners or multiple crowns in a cluster, fruit over a very long period with larger fruit than the common wood strawberry, and are usually propagated by seeds or division of the plants. The type in cultivation is usually everbearing and produces few runners. Plants tend to lose vigour after a few years due to their abundant fruiting and flowering with final decline caused by viral diseases.[15] Large-fruiting forms are known since the 18th century and were called "Fressant" in France.[16] Some cultivars have fruit that are white or yellow when fully ripe, instead of the normal red.
Cultivars that form stolons are often used as groundcover, while cultivars that do not may be used as border plants. Some cultivars are bred for their ornamental value. Hybrids, Fragaria × vescana, have been created from crosses between woodland strawberry and garden strawberry. Hybrids between the woodland strawberry and the European species Fragaria viridis were in cultivation until around 1850, but are now lost.[17]
Alpine strawberry has an undeserved reputation among home gardeners as hard to grow from seed, often with rumors of long and sporadic germination times, cold pre-chilling requirements, etc. In reality, with proper handling of the very small seeds (which can easily be washed away with rough watering), 80% germination rates at 70 °F (21 °C) 1–2 weeks are easily achievable.
Alpine strawberries are sometimes included as edging plants in herbaceous borders.[18]
Forms with runners are still found in old gardens.
Curious mutations have arisen and are sometimes grown by plantsmen and other connoisseurs of the unusual:
F. vesca contains the ellagitannin agrimoniin which is an isomer of sanguiin H-6.[23]
Fragaria vesca, commonly called the wild strawberry, woodland strawberry, Alpine strawberry, Carpathian strawberry or European strawberry, is a perennial herbaceous plant in the rose family that grows naturally throughout much of the Northern Hemisphere, and that produces edible fruits.
The Latin specific epithet vesca means "thin, feeble".
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