Western Wheatgrass

Western Wheatgrass (Agropyron smithii)

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

Western wheatgrass, also known as bluejoint, is a native grass. It produces dense stands on clay soils in association with green needlegrass, on saline soils with alkali-tolerant grasses and in sparse stands on upland sites with blue grama or bluebunch wheatgrass. It frequently occurs as the dominant grass throughout the area. It also occurs on abandoned, cultivated fields where the original stand of western wheatgrass was not entirely eliminated by cultivation.

It has several characteristics that make it exceedingly valuable for use in revegetation and erosion control. Its hardiness and drought resistance and its capacity to spread by underground rhizomes have outstanding value for conservation. It can survive drought and also flooding in shallow lake beds subject to overflow or excess surface drainage from spring run-off.

Description

Western wheatgrass is a long-lived, sod-forming perennial. It has a well-developed root system with a mass of surface roots feeding to a depth of 8 inches and deep-feeding roots that penetrate to a depth of 60 inches. Thus, the plant is well adapted to survive drought and to take advantage of light rains that soak only the top surface of the soil.

Plant growth is vigorous, with seed heads at a height of 2 to 3 feet and leaves 8 to 12 inches long. The leaf blades do not droop, but are more or less stiff and erect. The leaves are blue-green, and the entire plant is covered with a greyish bloom, which gives it a distinctive coloration. The seed heads are 2 to 6 inches long, and the seed is about twice as large as crested wheatgrass.

Adaptation

Western wheatgrass is adapted to a wide range of soils, but prefers the heavy and somewhat alkaline soils characteristic of shallow lake beds or along intermittent water courses that receive excess surface drainage water from spring run-off. Western wheatgrass is generally found growing in almost pure stands or in mixtures with other grasses. It is best adapted to well-drained bottomlands and grows well on heavy clay soils. This grass can grow through thick layers of silt along streams and can withstand considerable flooding. Western wheatgrass is winterhardy and drought resistant.

Limitations

Good stands of western wheatgrass are difficult to establish from seed due to seed dormancy and poor seedling vigor. Seed lots containing a high percentage of dormant seed should be stored for at least one year before using for planting purposes. A dormant (late fall) planting should be made to improve western wheatgrass stands. The cool, moist soil conditions during the winter months help to reduce the seed dormancy and result in higher seed germination the next spring. Plants develop slowly from seed, and because the young seedlings are small and inconspicuous, the new stand often appears a failure. However, the plants spread rapidly by rhizomes and provide the cover desired by the second year.

Use for Hay

Western wheatgrass produces leafy and nutritious hay. The yield of hay depends greatly upon moisture during the early part of the growing season. It produces excellent yields on spring-flooded sites.

It has a protein content of about 18 percent in early May, but this declines to about 4 percent by October. The digestible carbohydrates increase from about 40 percent to 50 percent during the same period. Feeding studies have shown that well-cured hay, cut late in the leaf stage, will be 60 percent digestible.

Use for Pasture

It is palatable to all classes of livestock during the early growing season. Growth begins early in the spring and continues until high temperatures stop its growth in the summer. Growth begins in the fall when temperature is cool and moisture is available. When mature, its leaves and stems become harsh and woody, but it cures well on the stem and provides good winter grazing.

Care should be taken to ensure that it is not grazed too closely. Heavy grazing during the growing season will reduce the forage yield, and may result in the death of many of the plants. Under continuous heavy grazing, it will disappear from stands.

* 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.