Environmental Description:  This Artemisia tridentata ssp. vaseyana-dominated shrub herbaceous association occupies the coolest and moistest climate zone of the Artemisia tridentata shrubland and shrub herbaceous complex. This open shrubland often occurs above lower treeline as patches within montane or subalpine coniferous forests. The climate regime is cool, semi-arid to subhumid, with yearly precipitation ranging from 25-60 cm. Much of the yearly precipitation falls as snow, which may cover the ground for long periods in winter. Temperatures are continental with large annual and diurnal variation. The elevation range for this type is wide, from about 1060 m (3500 feet) in eastern Oregon and Washington, 1800-2400 m (6000-8000 feet) on low mountain slopes and valleys in Montana, to well over 3000 m (9850 feet) in the mountains of northern Nevada, Idaho, Montana, Wyoming, and Colorado. Landscape positions are variable as well, but primarily are deep-soiled to stony flats, valley bottoms, flat terraces, ridges, nearly flat ridgetops, and mountain slopes. All aspects are represented, and slopes range from nearly flat to very steep. Soils generally are moderately deep to deep, somewhat well-drained, and of loam, sandy loam, clay loam, or gravelly loam textural classes, often having a substantial volume of coarse fragments. The soils are derived from a variety of parent materials, although sandstones, limestones, basalts, and crystalline rocks are commonest. In some cases, soils supporting stands of this association are unstable and prone to mass movement. In subalpine environments, these shrub herbaceous communities are found on deeper soils than Artemisia arbuscula subalpine shrublands. Trees are uncommon, but individuals of Pinus ponderosa, Cercocarpus ledifolius, Populus tremuloides, Juniperus occidentalis, Juniperus scopulorum, Pinus albicaulis, and Abies lasiocarpa may occasionally occur.

Adjacent vegetation is highly variable. In the Great Basin and Rocky Mountains, adjacent communities typically include Pinus ponderosa forests, Pinus - Juniperus or Cercocarpus ledifolius woodlands, Populus tremuloides forests, Artemisia arbuscula, Artemisia rigida, Artemisia tridentata ssp. wyomingensis, and Artemisia tridentata ssp. tridentata shrublands, and herbaceous meadows. In the Blue Mountains, East Cascade Range, and in the Okanogan Highlands, these shrublands are found in a matrix with Juniperus occidentalis, Pinus ponderosa, Pinus albicaulis, and Abies lasiocarpa forests and woodlands. In Montana, adjacent vegetation includes Festuca idahoensis and Pseudoroegneria spicata grasslands.