The Palouse Prairie is a temperate bunchgrass grassland of the Columbia Basin spanning eastern Washington, western Idaho, north-central Oregon, and south-central British Columbia. Its rolling hills were originally dominated by perennial cool-season grasses such as bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, and giant wildrye. The climate brings warm, dry summers and cold winters, with low precipitation (about 571 mm a year) falling mostly in winter. Notably, roughly 99.9% of the prairie has been converted to agriculture, chiefly wheat, making it one of the most endangered ecosystems in the United States.

At a glance

About the temperate grasslands, savannas & shrublands biome

Temperate prairies, steppes, and pampas of grasses and forbs with few trees, under continental climates of hot summers and cold winters. Their deep, fertile soils have made them among the most extensively converted biomes for agriculture.

National refinement sub-regions

Catalog plants suited to this ecoregion

Computed from each plant's stated USDA zone range against this ecoregion's USDA Plant Hardiness Zone Map 2023 (1991-2020 climatology) via ArcGIS FeatureServer published current zone range, with the CHELSA mid-century warming delta applied for the projection. Plants whose stated range falls outside both the current and projected zone end up dropped; the rest land in one of the three buckets below.

Collections for this ecoregion

Curated multi-plant collections whose members all fit this ecoregion's zone range — no won't-grow members smuggled in. Overall fit class shown per collection is the weakest link across its members.

Related ecoregions