Back to Forage Publications

Streambank Wheatgrass (Agropyron riparian)

Plant Species
From Montana Interagency Plant Materials Handbook *
 By S. Smoliak, R.L. Ditterline, J.D. Scheetz, L.K. Holzworth, J.R. Sims, L.E. Wiesner, D.E. Baldridge, and G.L. Tibke

Streambank wheatgrass is native to the northwestern United States and adjacent to Canada. Despite its name, it is not restricted to riparian sites, but has good drought tolerance. It is especially suitable for use in soil and water conservation work. Its dense, low-growing sod is highly resistant to erosion. The top growth is relatively short and fine-leaved, and requires a minimum of maintenance.

Streambank wheatgrass is used wherever a rapid-establishing, drought-tolerant ground cover is required, such as borrow pits, spoil banks, roadsides, pond and irrigation banks and airport surfaces. The seed germinates quickly and seedlings grow rapidly. The strong rhizomes spread rapidly to give complete erosion control in a short time, but it is not weedy like reed canarygrass in irrigation ditches or quackgrass in crop fields.

Little seed is produced from solid stands; so there is no danger of the grass spreading to irrigated cropland.

Streambank wheatgrass makes a permanent lawn for homes and playgrounds, and, when established, requires infrequent watering and minimum maintenance. It can also be used for parking areas and in machinery yards.

Streambank wheatgrass is easily crowded out by other grasses if the site is wet.

Description

Streambank wheatgrass is a long-lived perennial that is very drought tolerant. It is a sod former that has deep roots and very strong rhizomes that enable the grass to spread rapidly to form a good ground cover.

The plants are short with narrow, tough, smooth leaves. The grass has leaves 4 to 10 inches long and stems 16 to 36 inches high. The seed head is 2 to 4 inches long. The seed is somewhat larger than that of crested wheatgrass.

The leaves are light greyish-green and are somewhat curled at the margins.

Seed heads are mostly awnless, smooth to hairy and seeds shatter readily at maturity. Streambank wheatgrass establishes readily from seed, but does not become a weed. Mature plants are easily killed by normal tillage operations.

Adaptation

At elevations lower than 3,500 feet the minimum mean annual precipitation required for establishment and growth of streambank wheatgrass is 12 inches. Above this elevation it has performed well with 9 inches of precipitation.

Streambank wheatgrass is adapted to soils that are moderately alkaline and have sandy to clayey texture. It will also grow on soils that range from shallow to deep. It is not tolerant to wet or poorly-drained soils.

Limitations

Streambank wheatgrass produces a low forage yield and since it is not especially palatable, it has limited value for livestock use. It is not competitive with other grasses on wet sites. When irrigated, the plants are susceptible to leaf and stem rust.

Streambank wheatgrass usually only produces seed for the first two harvest years with the third harvest yield not normally economic. Seed shatter is a problem. Very little seed is produced under dryland conditions.

Use for Hay

Streambank wheatgrass is not normally recommended for forage production because the plants are short, have narrow, smooth leaves and are not especially palatable to livestock.

It is the lowest yielding of all the cultivated wheatgrasses on dryland or irrigated land. The low yields are attributed to the predominantly leafy growth.

Use for Pasture

Although it is not usually recommended, streambank wheatgrass can be used for pasture, even though the plants are short and not especially palatable. The leafy growth has a well-balanced nutrient composition.

Seed Production

Seed is normally produced under irrigation and has average seed produc-tion of about 200 pounds per year. Seeds are smooth, awnless and easily handled and processed. Seed heads are highly susceptible to shatter, and seed must be processed to break up multiple florets. Economical seed crops are usually only produced the first two harvest years and the grass then becomes "sodded in" and thereafter very few stems are formed.

 

* The Montana Interagency Plant Materials Handbook (EB69) is no longer in print, but is available for viewing in
Montana County Extension Service and National Resource Conservation Service Offices.