Elymus lanceolatus is a species of grass known by the common names thickspike wheatgrass and streamside wheatgrass. It is native to North America, where it is widespread and abundant in much of Canada and the western and central United States. There are two subspecies, ssp. lanceolatus occurring throughout the species' range and ssp. psammophilus occurring in the Great Lakes region. Elymus lanceolatus is a perennial, low growing, rhizomatous grass that actively grows in summer and spring. This plant is native to semiarid regions of the United States. Elymus lanceolatus is polymorphic, capable of growing in high altitude regions of the Rocky Mountains or at sea level near the Great Lakes in the United States. The bloom period for E. lanceolatus is mid-spring, and it is available commerciall