Submontane to montane, trans-continental North American grass within boreal, temperate and cool mesothermal climates. Occurrence decreases with increasing elevation and precipitation. Characteristic of moisture deficient sites.
Sandy. rocky, strongly drained and shallow soils on water shedding sites.
Nitrogen-poor soils (more humus forms).
Very dry to moderately dry.
Sporadic in open-canopy, young-seral forests. Climax on rock outcrops. Secondary successor of burned or cut sites.
Rocky outcrops in Garry oak ecosystems.