The scientific name of crested wheatgrass is Agropyron cristatum (L.) Gaertn. (Poaceae) [30,56]. Wheatgrasses (Triticeae), including crested wheatgrass, frequently hybridize and often produce fertile crosses [11,33,115]. Crested wheatgrass readily crosses with desert wheatgrass (A. desertorum) to produce fertile hybrids, the most common of which is called 'Hycrest.' Some systematists do not consider crested and desert wheatgrass to be distinct species [54]

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Crested wheatgrass has been planted throughout North America in a variety of ecosystems; the appearance of the species within a specific cover type does not necessarily indicate that crested wheatgrass is particularly well adapted to those climatic conditions.

In the Great Basin in Nevada, crested wheatgrass thrives in mesic communities with big sagebrush (Artemisia tridentata), basin wildrye (Elymus cinereus), Sandburg bluegrass (Poa secunda), Columbia needlegrass (Achnatherum nelsonii ssp. dorei), and slender wheatgrass (E. trachycaulus) [38].

Vegetation typings describing communities dominated by crested wheatgrass follow.

Phyto-edaphic communities of the Upper Rio Puerco Watershed, New Mexico [43]
Plant associations of the Crooked River National Grassland [61

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Crested wheatgrass is an introduced species, originally from Russian and Siberian steppe habitats. It has been planted from Alaska south to California, throughout western Canada, east in the United States to Ohio, and south to Texas. It was first successfully established in the United States between 1907 and 1913 [35]. Crested wheatgrass and desert wheatgrass were considered distinct species upon their first introduction to the United States in 1906, but since, the two species have often been referred to and treated as one [34]. Crested and desert wheatgrass became prevalent in the United States in the 1930s when they were used to seed abandoned cropland. Crested wheatgrass is most common in the northern Great Plains, especially North and South Dakota, eastern Montana and Wyoming, and in southern Saskatchewan and southeastern Alberta. The grass is used throughout the arid and semi-arid regions of the West [105]. Crested and desert wheatgrass seedings have been established on 10 million acres (3.2 million ha) [5] and, by some accounts, as much as 26 million acres (10.4 ha) in North America [78].