Seeds usually germinate in 21 days under ideal laboratory conditions. Thickspike wheatgrass regenerates vegetatively through rhizomes, as well as sexually via wind-dispersed seeds. Due to its matted root system, other species have difficulty establishing in thickspike stands. Thickspike wheatgrass occurs in grasslands and sagebrush deserts on low dry plains, dry hillsides, exposed flats and ridges, benches, and well-drained meadows. Although thickspike wheatgrass is best adapted to sand, sandy loam, and loam soils, it is also found on heavy alkaline flats and weakly saline soils.
Plants occur over wide elevational ranges.
This cool-season grass produces its best growth in spring. Thickspike wheatgrass blooms from May to July.