Western Wheatgrass

Reg Newman, BC FLNR
Scientific name: 

Pascopyrum smithii (Rydb.) A. Love

Native Grass
Annual precip. min (mm): 
Annual precip. max (mm): 
Seed size: 
Seeds per kg: 
PR Suitability note: 
Western wheatgrass is found in native grassland communities in the Peace Region, sometimes with Junegrass, slender wheatgrass and northern wheatgrass.
Key considerations: 
Western wheatgrass has high value for erosion control, but stands can take several years to become established. Should be limited in mixtures when other species are desired because its spreading root system makes it very competitive. Good forage value, although production is less than other species. Tolerance for alkaline soils with pH up to 9.0 Varieties have been developed. Where there is a native plant community objective, and a desire to maintain a high level of ecological integrity, seed from local ecotypes or wild populations may be preferred.
General Description: 

Western wheatgrass is a native cool-season perennial grass that grows from conspicuous white rhizomes, and is strongly rhizomatous. Western wheatgrass is a sub-dominant in plant communities with bluebunch wheatgrass and Idaho fescue, and is dominant on many sites on mixed-grass prairie east of the Rockies. On clay sites it is usually found with green needlegrass (Nassella viridula (Trin.) Barkworth - syn. Stipa viridula).

The shallow roots of western wheatgrass extend to 25 cm (10 in.) deep whereas feeder roots can be 150 cm deep (59 in.). The roots are known to creep aggressively in some conditions.

Smooth stems grow to 20 to 100 cm (8 to 39 in.) tall and are very erect. The leaves are rigid, flat, 6 mm wide, glaucous, blue, and grow at a 45 degree angle to the stem. The leaves are also ridged, rough, and veiny. The auricles are often purple, giving the plant its common name. Seed heads are 7 to 15 cm long (3 to 6 in.) dense spikes with single spikelets at each node. Each spikelet is 6 to 10 flowered glumes that are 10 to 12 mm long. They are rigid and almost flat sided in the middle not broadened. 

Seeds are 10 to 12 mm long; the lemma sometimes having a short awn. Western wheatgrass is cross-pollinating often via wind, and is self-incompatible.

Western wheatgrass is native to the mixed-grass prairies of North America.
Western wheatgrass is found throughout British Columbia and the rest of North America except in the southeastern United States. It is locally common in northeastern British Columbia as part of the Peace River grasslands.
Habitat and climate: 
Western wheatgrass is found on moist to dry slopes in grassland and montane zones. It can often be found where water pools in the spring.
Western wheatgrass is used for livestock and wildlife forage on native ranges. It is occasionally used as native hay on sites that might receive supplemental moisture. It is used for erosion control and reclamation of disturbed sites, but is not compatible with strongly competitive non-native species.
Optimal time of grazing use: 
Western wheatgrass can be used in spring, summer, and fall and as stockpiled grazing as it cures on the stem.
Recovery after use (rating): 
Recovery after use: 
Annual spring use will usually cause western wheatgrass to decrease. It usually responds favorably to rest rotation or deferred rotation grazing systems. Western wheatgrass should be allowed to reach 15 cm (6 in.) of growth before grazing in spring.
Forage yield (rating): 
Forage yield: 
Western wheatgrass has relatively low forage production compared to other species.
Palatability/Nutritional Value: 
Western wheatgrass is considered good forage and is palatable to livestock and wildlife. In June digestibility is 60% with crude protein around 14%. By September digestibility is 50% and crude protein is 8.5%. Provides nutritious winter pasture and hay.
Longevity (rating): 
Western wheatgrass is long lived.
Persistence (rating): 
Western wheatgrass has reasonable persistence if grazing is managed.
Invasiveness (rating): 
Western wheatgrass is not considered invasive but can spread into adjoining areas under ideal conditions.
Competitiveness (rating): 
Western wheatgrass can be competitive as it becomes established, spreading mostly by rhizomes. The percentage in mixtures should be kept low to prevent western wheatgrass from dominating stands.
Weed resistance (rating): 
Weed resistance: 
Under the appropriate site conditions western wheatgrass can provide good weed resistance once it is established.
Erosion control (rating): 
Erosion control: 
Western wheatgrass has excellent value for erosion control because of its spreading root system. However, full cover will be delayed as stands take several years to become fully established.
Drought tolerance (rating): 
Drought tolerance: 
Western wheatgrass has very good drought tolerance.
Winter hardiness (rating): 
Winter hardiness: 
Western wheatgrass has excellent winter hardiness.
Soil texture preference (rating): 
Soil texture preference: 
Western wheatgrass prefers fine- to medium-textured soils.
Flooding tolerance (rating): 
Flooding tolerance: 
Western wheatgrass can stand approximately 5 weeks of spring flooding.
Salinity tolerance (rating): 
Salinity tolerance: 
Western wheatgrass has moderate salinity tolerance.
Acidity tolerance (rating): 
Acidity tolerance : 
Western wheatgrass is not recommended for acidic soils.
Pests and/or disease threats: 
Primary pests include grasshoppers, ergot, and stem and leaf rusts.
Ease of establishment (rating): 
Ease of establishment: 
Western wheatgrass is relatively easy to establish, but seedlings tend not to be very vigorous. Germination is sometimes poor and stands can take several years to become fully established through rhizome development.
Application requirements: 
Western wheatgrass is sometimes established from sod. Some form of minimal site disturbance after broadcast seeding is recommended.
Suggested mixtures: 
Western wheatgrass works well in mixtures but creeps aggressively so should be kept to a low percentage.
Management considerations: 
Proper grazing management is required to maintain the productivity of western wheatgrass. After approximately 5 years, stands may become sod-bound, making stand renovation necessary to maintain productivity.