Elymus repens, quackgrass
Snyder, S. A. 1992. Elymus repens, quackgrass. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/elyrep
| Abbreviation | Common Name | Scientific Name | Classification | Status |
|---|---|---|---|---|
| Plants | ||||
| ELYREP | quackgrass | Elymus repens | Life Form: Plants/Graminoid Kingdom: Plantae Class: Monocot Order: Cyperales Family: Poaceae Genus: Elymus | Fed. Protected: No Nativity: Nonnative Invasiveness: Invasive |
Taxonomy
The currently accepted scientific name for quackgrass is Elymus repens (L.) Gould (Poaceae) [51]. One variety and six forms have been recognized [18]. Short descriptions will follow each here, rather than in Botanical Description. Each form and variety is followed by single descriptors for glue, lemma, and rachis:
- E. r. aristatum—oblong, awned, smooth
- E. r. trichorrhachis—oblong, blunt, hairy
- E. r. pilosum—oblong, awned, hairy
- E. r. vaillantianum—lanceolate, awned, smooth
- E. r. heberhachis—lanceolate, blunt, hairy
- E. r. setiferum—lanceolate, awned, hairy
- E. r. var. subulatum—lanceolate, blunt, smooth
In the laboratory, quackgrass has been successfully crossed with the following species [2,18]:
- E. r. x E. arenaurius = Agroelymus adamsii Rousseau
- E. r. x Pseudoroegneria spicata
- E. r. x Agropyron cristatum.
Synonyms
- Agropyron repens (L.) Beauv.
- Elytrigia repens (L.) Desv. ex Nevski [4]
Other Common Names
couchgrass, witchgrass, quitchgrass, quickgrass, chiendent
Notes
The Research Project Summary titled "Herbaceous responses to seasonal burning in experimental tallgrass prairie plots" provides information on postfire response of quackgrass in experimental prairie plots that was not available when this species review was originally written. To find this summary, search FEIS for this species by entering the species name on the Advanced Search page and selecting “Fire Study” as the publication type.
General Distribution
Quackgrass is widely distributed across North America: from coast to coast, south to the southwestern border states and north to Alaska [44]. It is also widespread throughout eastern Canada [18]. Because quackgrass does not tolerate long, hot summers it is absent from the Gulf Coast States (except northern Texas) [36].
States and Provinces
- United States: AK AZ AR CA CO CT DE HI ID IL IN IA KS KY ME MD MA MI MN MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SD TN TX UT VT VA WA WV WI WY
- Canada: NF NS ON PQ
Site Characteristics
Quackgrass can tolerate some saline conditions in the low-lying valleys of Utah [26]. Salt-tolerant cultivars have been developed by crossing quackgrass with bluebunch wheatgrass [42]. Elevational range in four western states follows [14]:
| State | Elevation (ft) | Elevation (m) |
|---|---|---|
| Utah | 5,100-8,200 | 1,554-2,499 |
| Colorado | 4,800-10,000 | 1,463-3,048 |
| Wyoming | 4,500-8,000 | 1,372-2,438 |
| Montana | 5,000-6,600 | 1,524-2,012 |
Plant Communities
Quackgrass.
Quackgrass invades gardens, yards, crop fields, roadsides, ditches, and just about any disturbed, moist area [21]. It invades mixed-grass prairies as well as oak (Quercus spp.)-hickory (Carya spp.) and whitebark pine (Pinus albicaulis) forests [1,24,49].
Some associate species of quackgrass include sedge (Carex spp.), bulrush (Scirpus spp.), rush (Juncus spp.), bluebunch wheatgrass, crested wheatgrass, red top (Agrostis alba), indiangrass (Sorghastrum nutans), bluestems (Andropogon spp., Schizachyrium spp.), smooth brome (Bromus inermis), poverty oatgrass (Danthonia spicata), panic grass (Panicum spp.), Kentucky bluegrass (Poa pratensis), common ragweed (Ambrosia artemisiifolia), prairie pepperweed (Lepidium densiflorum), prairie dropseed (Sporobolus heterolepis), Canada thistle (Cirsium arvense), Carolina geranium (Geranium carolinianum), and bracken fern (Pteridium aquilinum) [1,5,11,15,24,26,28].
Botanical Description
Quackgrass is a cool-season, exotic, perennial, rhizomatous graminoid. Its stems are erect, decumbent, and may reach heights of 1 to 3 feet (0.3-1 m) but more commonly grow to 0.25 to 1 inch (0.5-2 cm) high [18,21]. Quackgrass is green to whitish, with hirsute to nonhirsute leaves and awned or nonawned lemmas [18,26]. Rhizomes can grow 23 inches (60 cm) or more from the main shoot before sending out stems [36] and grow as deep as 8 inches (20 cm) [26]. Dahlberg [12] described how to identify seeds of the Agropyron genus to distinguish between desirable and undesirable species.
Raunkiaer Life Form (Raunkiaer 1934)
- Chamaephyte
- Geophyte
Seasonal Development
Quackgrass flowers from June through August in Colorado, Wyoming, and Montana; and from June through July in North Dakota [14].
Flowering quackgrass.
Optimum temperatures for growth are between 68 and 77 degrees Fahrenheit (20 and 25 deg C), with no growth occurring above 95 degrees Fahrenheit (35 deg C) or below 35 degrees Fahrenheit (2 deg C) [16,36]. Primary rhizome growth begins in late May or early June and then again in September and October [36]. Rhizome growth seems to be favored by low temperatures [50 deg F(10 deg C)] and long days (18 hours) [36].
Regeneration Processes
Quackgrass propagates mainly by rhizomes but also reproduces by seed. Seed production, however, is reported to be as low as 25 viable seeds per plant per season [36]. Studies in Alaska showed that seed viability may vary depending on how deep and long the seeds have been buried; viability is reduced significantly after burial for 21 months [10]. In greenhouse trials, dormancy of seeds buried 6 inches (15 cm) deep was 16 percent, while dormancy of seeds buried 0.8 inch (2 cm) deep was only 5 percent [9]. Cross-pollination is necessary for seed production [44]. Dormancy in rhizome buds has been related to nitrogen deficiencies, which peak in June [8]. Sod mats can be as dense as 367 meters of rhizomes per square meter [36].
Successional Status
Quackgrass is an early seral dominant in disturbed areas [15,22,27].
Immediate Fire Effects
Late spring fires generally reduce quackgrass cover, flowering and biomass, while early spring fires can increase these.
A May burn in oak savannas of Wisconsin significantly reduced quackgrass and halted flowering [13]. Similar results (reduction in biomass and cover) have been shown for other areas [23,28]. Burning quackgrass on a biennial schedule for several years has been effective in eradicating this species [1,3].
Postfire Regeneration Strategy (Stickney 1989)
- Rhizomatous herb, rhizome in soil
Fire Adaptations
Quackgrass is adapted to certain seasonal fires because of its rhizomes.
Plant Response to Fire
Quackgrass cover can increase following fire.
Five annual late April to early May burns in Minnesota resulted in a decrease in quackgrass height but an increase in cover [5]. Plant vigor was reduced and flowering stopped, but quackgrass continued to spread into adjacent areas. At the time of the April burns, plant height was between 3.9 and 5.9 inches (10-15 cm), and during the May burn, heights were between 5.9 and 9.8 inches (15-25 cm). May and June burns on North Dakota grasslands "harmed" quackgrass in the first postburn season, but quackgrass recovered to almost preburn levels by the second postburn season. Following the late June fire, quackgrass showed a slight increase in cover, height, shoot density, production, and flowering [39]. Wisconsin grassland fires in March caused an increase in seed production by July and August [23].
Fire Regimes
For fire regime information, search FEIS for this species by entering the species name or acronym on the home page and selecting “Fire Regime” as the publication type.
Fire Management Considerations
Cool-season grasses such quackgrass are best eliminated with early spring burns [20,31,34]. Cool-season grasses can grow in the fall following summer dormancy; therefore, fall burns might also help reduce undesirable cool-season grasses [41].
Federal Status
None
Other Status
No entry.
Importance to Wildlife and Livestock
Quackgrass provides cover for numerous small rodents, birds, and waterfowl [30,45].
Palatability and Nutritional Value
Many palatable hybrid crosses of quackgrass and other species have been developed and planted for livestock [2]. Feeding trials in Minnesota showed that a quackgrass biotype was as palatable as alfalfa (Medicago spp.) [37]. In cattle grazing trials in Montana, preference was shown for some clonal lines of a quackgrass-bluebunch wheatgrass (Pseudoroegneria spicata) cross [46].
The degree of use shown by livestock for quackgrass in five western states has been rated as follows [14]:
| Species | Colorado | Montana | North Dakota | Utah | Wyoming |
|---|---|---|---|---|---|
| Cattle | Good | Good | Good | Good | Good |
| Domestic sheep | Fair | Fair | Fair | Good | Fair |
| Horses | Good | Good | Good | Good | Good |
Quackgrass has been rated fair in energy value and poor in protein value [14]. However, food value studies in Minnesota showed that quackgrass had as much crude protein as alfalfa during May [37]. These authors list concentrations of 10 minerals found in quackgrass in Minnesota. Results of Alaskan studies showed that quackgrass did not contain enough magnesium required for ruminant digestion nor did it have a high mineral content. However, digestibility was 64 percent and greater in three harvest trials [38].
Cover Value
The degree to which quackgrass provides cover for wildlife has been rated as follows [14]:
| Species | Montana | North Dakota | Utah |
|---|---|---|---|
| Small mammals | Good | Fair | Good |
| Small nongame birds | Fair | Good | Fair |
| Upland game birds | Good | Good | Fair |
| Waterfowl | Good | Good | Fair |
Value for Rehabilitation or Restoration of Disturbed Sites
Quackgrass has been used to revegetate mine tailings in Nova Scotia [48]. A quackgrass/Fairway crested wheatgrass hybrid may be useful for revegetating mine spoils and roadsides [2].
Other Uses
No entry.
Other Management Considerations
Although quackgrass is considered an undesirable weed species it is often crossed with other wheatgrasses (Agropryon spp.) to create hybrids for grazing [2,6]. It can be controlled with chemicals such as glyphosate, dichlobenil, and fauzifop [50]. Sometimes, however, chemicals are not effective. In Wisconsin, 2,4-D applied to quackgrass caused a slight increase in quackgrass cover and no effect on stem density [23]. In Midwestern prairies, mowing and raking significantly reduced quackgrass biomass and prevented flowering the following growing season [13]. Mowing, burning, and chemical application combined may be the best way to eradicate quackgrass [33].
Table A1— Forest and range ecosystems, Bureau of Land Management (BLM) physiographic regions, Kuchler plant associations, Society for American Foresters (SAF) forest cover types, and Society for Rangeland Management (SRM) rangeland cover types in which this species occurs.
Forest and Range Ecosystems (Garrison et al. 1977)
- FRES10 White - red - jack pine
- FRES14 Oak - pine
- FRES15 Oak - hickory
- FRES18 Maple - beech - birch
- FRES19 Aspen - birch
- FRES29 Sagebrush
- FRES32 Texas savanna
- FRES36 Mountain grasslands
- FRES37 Mountain meadows
- FRES38 Plains grasslands
- FRES39 Prairie
- FRES41 Wet grasslands
- FRES42 Annual grasslands
BLM Physiographic Regions (Bernard and Brown 1977)
- 1 Northern Pacific Border
- 2 Cascade Mountains
- 3 Southern Pacific Border
- 4 Sierra Mountains
- 5 Columbia Plateau
- 6 Upper Basin and Range
- 7 Lower Basin and Range
- 8 Northern Rocky Mountains
- 9 Middle Rocky Mountains
- 10 Wyoming Basin
- 11 Southern Rocky Mountains
- 12 Colorado Plateau
- 13 Rocky Mountain Peidmont
- 14 Great Plains
- 15 Black Hills Uplift
- 16 Upper Missouri Basin and Broken Lands
Kuchler Plant Associations (Kuchler 1964)
- K055 Sagebrush steppe
- K056 Wheatgrass - needlegrass shrubsteppe
- K063 Foothills prairie
- K064 Grama - needlegrass - wheatgrass
- K065 Grama - buffalograss
- K066 Wheatgrass - needlegrass
- K067 Wheatgrass - bluestem - beedlegrass
- K068 Wheatgrass - grama - buffalograss
- K069 Bluestem - grama prairie
- K074 Bluestem prairie
- K100 Oak - hickory forest
SAF Cover Types (Eyre 1980)
- 1 Jack pine
- 15 Red pine
- 16 Aspen
- 20 White pine - northern red oak - red maple
- 21 Eastern white pine
- 27 Sugar maple
- 19 Grey birch - red maple
- 51 White pine - chestnut oak
- 55 Northern red oak
- 108 Red maple
- 208 Whitebark pine
SRM Rangeland Cover Types (Shiflet 1994)
- No entry
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