Adaptation: Streambank wheatgrass are similar to western wheatgrass in appearance, except they are not as coarse, their rhizomatous trait is not as aggressive, and their coloration is somewhat greener. They are more drought tolerant than western wheatgrass. In comparison to western wheatgrass, they “green up” and “head out” earlier and total biomass production is generally lower. Both wheatgrasses do better on medium to coarse textured soils. Streambank wheatgrass can be found on slightly heavy to medium to coarse textured soils. Western wheatgrass may be a better choice on heavy textured soils if rainfall is high enough. They will tolerate slightly acidic to moderately saline conditions. They are cold tolerant, can withstand moderate periodic flooding in the spring, are moderately shade tolerant, and very tolerant of fire. They will not tolerate long periods of inundation, poorly drained soils, or excessive irrigation. Snake River wheatgrass prefers deep to shallow medium to coarse textured soils.
On native sites, streambank and Snake River wheatgrasses are most abundant in the 8 to 20 inch annual precipitation zones. Seeded varieties do best with 10 to 20 inches of precipitation. They have been seeded as low as 5 to 9 inches of precipitation with some success. The natural geographic range of E. lanceolatus ssp. lanceolatus is from near sea level in the Great Lakes region to 10,000 feet in the Rocky Mountains. The natural range of streambank wheatgrass is primarily the intermountain west. E. lanceolatus ssp. lanceolatus is a very polymorphic species and is a component of the vegetation on such diverse sites as stabilized sand dunes in eastern Washington, glacial outwash fans in Montana and loess (wind blown silt loam) soils in southern Idaho. They are components of many native plant communities and generally occupy less than 10 percent of the overall composition. An exception to this may be short periods following fire in Juniper stands, when they may nearly dominate the site.
Species often associated with these wheatgrasses include the following: the big sagebrush (Artemisia tridentata) complex, juniper (Juniperus spp.), needlegrasses, sand dropseed (Sporobolis airoides), prairie sandreed (Calamovilfa longifolia), bluebunch wheatgrass, Snake River wheatgrass, and Idaho fescue (Festuca idahoensis).
Planting: These species should be seeded with a drill at a depth of 1/2 inch or less on medium to fine textured soils and 1 inch or less on coarse textured soils. Single species seeding rates recommended for both grasses are 6 to 8 pounds Pure Live Seed (PLS) or 20 to 25 PLS per square foot. If used as a component of a mix, adjust to percent of mix desired. For mined lands and other harsh critical areas, the seeding rate should be increased to 40 to 50 PLS per square foot. Mulching and light irrigation are beneficial for stand establishment.
The best seeding results are obtained from seeding in very early spring on heavy to medium textured soils and in late fall on medium to light textured soils. Late summer (August - mid September) seedings are not recommended unless irrigation is available. Pre-chilling seed aids germination. Seedling vigor is good to excellent, exceeding that of western wheatgrass, but less than crested wheatgrass (Agropyron cristatum).
Both wheatgrasses establish fairly quickly, more quickly than western wheatgrass. They are the most rapidly establishing native species next to slender wheatgrass (Elymus trachycaulus). They are compatible with other species and can be used in seeding mixtures. They should not be seeded with strongly competitive introduced species. Under favorable conditions, they can become a good weed barrier.
Stands may require weed control measures during establishment, but application of 2,4-D should not be made until plants have reached the four to six leaf stage. Mow when weeds are beginning to bloom to reduce seed development. Grasshoppers and other insects may also damage new stands and the use of pesticides may be required.