To Grass Species

Idaho Fescue (Festuca idahoensis)

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

Idaho fescue is a native, perennial bunchgrass that is deep-rooted with fine, dense, basal foliage. The plants range from 1 to 3 feet tall. It is indigenous to open woods, rocky slopes of the mountains and foothills of the intermountain and northern Great Plains region. Idaho fescue is considered a key indicator of the condition and trend of native forage stands.


Idaho fescue is a cool-season, densely tufted, perennial bunchgrass. The characteristic bluish-green leaves are tightly inrolled and rough to the touch. The extensive, fibrous root system is a distinct black or dark brown color. The narrow panicle is 3 to 8 inches long, with branches ascending or oppressed, somewhat spreading during pollination. The spikelets are five- to seven-flowered, with awns up to 1/4 inch long. This species is shade tolerant, and often functions as an understory plant; however, it also occurs on exposed sites as a dominant plant.


This grass grows on a variety of soils, but reaches best growth on well-drained, sandy or gravelly loams. It can be considered moderately tolerant to drought. It is not tolerant of saline-alkaline soils, and only slightly tolerant of any extremes in acidity. It withstands cold well, especially where snow cover is complete. It is adapted for critical area stabilization in mountain and foothill sites. It can best be utilized in a mixture, particularly in situations where native plants are required.


Idaho fescue is not as drought-tolerant as either hard fescue or sheep fescue. This grass will not tolerate poorly drained soils or a high water table. Seedling emergence is greatly hindered by any soil crusting. Stands of this species are slow to develop, but no slower than the other fine-leaved fescues.

Use for Hay

Idaho fescue has been harvested as native hay where it is growing in higher rainfall areas, and is growing on exposed gentle slopes. It is not used as a seeded crop specifically for hay production.

Use for Pasture

Idaho fescue is a valuable range grass, both for livestock and big game animals. It is palatable in the spring, and cures well on the stem, making good fall and winter forage. It is moderately resistant to grazing and trampling, and will be replaced by less desirable species under continued, heavy use. It will actually increase under moderately-heavy grazing by cattle on rough fescue ranges. Average protein and phosphorus contents are high during the spring, but decrease during the summer.

Seed Production

Idaho fescue is a relatively poor seed producer. Most of the seed on the commercial market is derived from native harvests. Under irrigated conditions, average seed production is 200 pounds per acre. The seeds readily shatter upon maturing.

* 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.