The intermountain bunchgrass type, like True Prairie, has been cultivated over large expanses due to the highly fertile soils that exist there. The topography is such that large areas remain in native grasslands.

Location. The intermountain bunchgrass type is situated between the Cascade Range and the Rocky Mountains in the northwestern states of Washington, Oregon, and Idaho. In western Montana, an area of intermountain bunchgrass grassland resides east of the Bitteroot range. Elevation ranges from 300 to 1200 meters.

Climate. Precipitation, which comes mainly in winter as snow, varies from 25 to 65 cm. Mountain barriers ameliorate the climate somewhat preventing excessively cold temperatures. The growing season, however, is short with growth starting in early spring and terminating in early July.

Vegetation. This grassland is characterized by bunchgrass, most notably bluebunch wheatgrass (Agropyron spicatum) and Idaho fescue (Festuca idahoensis). Prairie junegrass, needlegrasses, and Sandburg bluegrass. There are numerous early spring forbs [balsamroot (Balsamorhiza) yarrow (Achillea) and mule's-ears (Wyethia)]. Much of this grassland has been invaded by downy brome (Bromus tectorum). In the southern part and drier areas, shrubby species have encroached as a result of fire absence. Big sagebrush (Artemesia tridentata), saltbrushes (Atriplex), rabbitbrush (Chrysothamnus), and bitterbrush (Purshia) are the common shrubby species. Daubenmire (1942) provides a detailed discussion on the vegetation of portions of the intermountain bunchgrass type.

Soils. Soils of the area are deep, fertile mollisols with high organic matter making them dark in color. Some areas in Montana have poorly developed soils (Entisols), but produce luxuriant vegetation. Loess deposits are the parent material for soils in the Washington and Oregon areas.

Management. Open rolling grassland areas support cattle grazing throughout the area with as little as 4 to as much as 16 hectares per animal unit required for the grazing season. On rougher topography and the more arid areas, sheep grazing also occurs. Though the area can be grazed throughout the spring, summer and fall, there is little summer grazing due to the absence of precipitation at that time. Numerous cool-season grasses are raised under irrigation in parts of the area giving rise to complementary grazing enterprises using range and tame pastures.