Big Prairie grassland
Palmer Dry grasslands represent only 8% of the plant cover in Glacier National Park. The relic fescue-wheatgrass prairies in the North Fork drainage resemble those in eastern Washington and western Idaho, but here the dominant grass is rough fescue. The fingers of prairie on the east side of Glacier Park, dominated by Idaho fescue and rough fescue, are a little more like the grasslands of the Great Plains, and similar to those occurring in the North Fork. Needlegrass, Junegrass, timber oatgrass and bluebunch wheatgrass are common in both places. There is a somewhat higher species diversity in the park's east-side grasslands compared to the Great Plains.
One attribute that the east and west sides of the park have in common is a major problem with exotic plant species. In the North fork prairies, leafy spurge and yellow toadflax have invaded disturbed areas and pose a major threat to native species. Control measures are very difficult, especially with the deep-rooted spurge.
On the east-side grasslands, non-native timothy grass was introduced intentionally for horse pasture in the 1920s or 30s, and spotted knapweed invades many disturbed areas. The spread of these exotic plants makes suitable grazing food unavailable to elk and deer, which impacts their populations along with predators. Only dogged, continuous control programs have any hope of reversing this trend.
Pinegrass is an inconspicuous native woodland grass which normally doesn't attract much attention. This grass species only flowers following wildfire, and after the large Moose Fire of 2001, pine grass suddenly sprouted flowering stalks ten times taller than their normal size and they seeded profusely. A similar display occurred following the 2003 fires.