Idaho Fescue
Festuca idahoensis

Idaho fescue. Collected along the trail toward Weippe Prairie northeast of Kamiah in Clearwater Co., Idaho, on 10 Jun 1806. (Source)

Idaho fescue is a vigorous, native, long-lived, perennial, cool-season, bunchgrass . Plants are strongly caespitose. Leaves are fine, dense, and mostly basal, with sheaths remaining firm and entire. Culms are densely tufted in large bunches, with tuft 6 to 10 inches (15-25 cm) high, usually more than 1/2 the length of culms. Culms are erect, from 1 to 3.3 feet  tall. Spikelets are 5- to 6-flowered, with large, awned seeds. Plants have a strong root system that can extend 16 inches deep in a 4-inch diameter plant. In well-drained soils, root biomass is greatest at 0.8- to 1.6-inch depths. Idaho fescue roots are infected with vesicular-arbuscular mycorrhizae, which may give it a competitive advantage over non-mycorrhizal plants and/or allow it to thrive on nutrient-poor soils or extreme environmental conditions. Idaho fescue reproduces from seeds and tillers.

Idaho fescue grows on many landforms, elevations, aspects, and soil types. It occurs at elevations from 990 feet  to nearly 13,200 feet. It thrives in areas of 15 inches mean annual precipitation or greater, but is also found in areas with lower precipitation. 

Since Idaho fescue occurs in a variety of ecosystems (grassland, sagebrush, forest, and alpine), it is probably most useful to look at site characteristics within each of these ecosystems.   In the grasslands of the Intermountain region, Idaho fescue occurs in valleys, canyons, benches, slopes, and rolling hills bordering sagebrush/grasslands, juniper woodlands, or the lower treeline. In the northern Rocky Mountains, Idaho fescue also occurs in mountain parks at upper elevations where tree growth is inhibited. Idaho fescue as one of the major grasses at 4,950-9,900 feet on Caribou National Forest, southeastern Idaho. In general, Idaho fescue starts growth in early spring, seeds mature by midsummer, and dispersal is prompt. (Source)

Value for Animals:
Idaho fescue provides important forge for several wildlife species. In Oregon, Idaho fescue is the main grass selected by elk and sheep in spring. Idaho fescue is an important component in elk diets throughout the Rocky Mountain region.  Elk and deer use the type as low-elevation winter range, and pronghorn use it year-round.  At intermediate elevations Idaho fescue is important spring-fall range, and at upper elevations it provides summer range for elk and mule deer. Idaho fescue plant associations are important deer habitat, but that Idaho fescue is not a preferred forage species. Idaho fescue is a common grass on pronghorn summer range in Yellowstone National Park. 

 Some Idaho fescue sites at moderately high elevations are used by bighorn sheep and Rocky Mountain goats as winter range. 

Northern pocket gophers eat primarily the leaves and stems of Idaho fescue in June through September, although they prefer forbs. 

Idaho fescue is a component of grizzly bear habitat in Yellowstone National Park and other locations.  Idaho fescue is a common under story component of grouse habitat in Oregon, Idaho, and Montana. (Source)

Idaho fescue is slow to establish, but once established, has abundant growth of fine leaves that provide effective ground cover, and high yields of tough, fine, fibrous roots that control erosion and improve soil structure. It has poor tolerance to salinity, although Ho suggests this may be overcome through inoculation with mycorrhizal fungi. Idaho fescue is suitable for year-round planting (fair in winter), has good stand maintenance, and retards or prevents the invasion of weeds once firmly established. Seedling emergence is greater when seed is protected with mulch or is mixed with an earlier seral, rapid-developing grass.

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