Elymus is a genus of perennial grasses belonging to the Poaceae, or grass, family. The grasses in this genus are generally referred to as wild rye or wheatgrass. Usually growing in tufts, these grasses typically have erect culms and flat or rolled leaf blades. They are characterized by their flowing foliage, which ranges in color from green to blue-green. These grasses bear flowers that are borne in bristly and skinny spikes and that are sometimes showy and can make good cut flowers.
There are about 170 species of these grasses, and almost half of the known Elymus species are found in Asia, mostly in China. These grasses usually grow in the temperate regions of both hemispheres. The most widespread species in North America are the E. cinereus, or giant wild rye; E. virginicus, or Virginia wild rye; and E. canadensis, or Canadian wild rye. There are also several species that are threatened and endangered, such as E. hystrix, or eastern bottlebrush grass; E. lanceolatus, or thickspike wheatgrass; and E. villosus, or hairy wild rye.
One Elymus species is listed as a noxious weed in several regions of the United States as well as in Canada. Known under the names quackgrass, quackgrass rye, and Medusa’s head, E. repens has been observed crowding out native species as well as reducing crop yields. Reports have shown that this grass may also cause seed contamination of seed grain crops, which reduces the value of their harvests. This grass can be difficult to control, though herbicides and crop rotation are effective in limiting its population. E. repens is native to Europe and was introduced to the United States in the 1600s.
Elymus grasses require full sun to grow effectively. They can live well in any type of soil as long as it is well drained, moist, and moderately fertile. Generally tolerant of drought, they are, however, susceptible to powdery mildew, tar spots, and other fungal diseases. These grasses are propagated by seed, though they may also be cultivated by dividing the clumps.
Most of the Elymus grasses can be used as forage for livestock. Some species, such as E. cinereus, or great basin wild rye, and E. magellanicus, or blue wheatgrass, are commonly used as ornamental grasses. They are usually planted as borders or beds in natural gardens or rock gardens. E. canadensis, or Canadian wild rye, has edible seeds that can be ground into flour for making bread. This particular species was an important food source for the Paiute Indians of southwestern North America.