South facing slopes, lateral moraine near Hollowell Park, Moraine Park museum, Headquarters area. Appears to be spreading on south facing slopes, lower elevations, and in recently disturbed areas. If all populations were added together, would cover an estimated area of 11-50 hectares.
Populations are widespread and dense and are likely inhibiting natural secondary succession.
Very common in western states and in Colorado from 4000 to 9000'. Common along roadsides, waste areas, misused pastures, rangelands, and cultivated crop areas. Open slopes, salt desert shrub, sagebrush, pinyon juniper, and less commonly in aspen and conifer communities. Found primarily in the 15-56 cm precipitation zones' although is found in many climatic areas. Sandy or gravely soils, does not grow well on heavy soils, or soils with high salts.