Leymus racemosus aka Mammoth Wild Rye

Leymus racemosus is a perennial grass in the Poaceae family. Its names include mammoth wild rye and Volga wild rye. Kew places its native range from southeastern and eastern Europe to Siberia and the Caucasus. It grows in temperate regions and occurs in dry, sandy ground. It also grows in parts of the western and midwestern United States.

This cool-season grass forms clumps but spreads fast through underground rhizomes. Its coarse leaves give it a bold form. The flat, narrow blades are glossy and steel blue. They reach about 0.7–1.3 feet [0.2–0.4 metres] long. Their width is less than one inch. The leaves lack hairs, and the stems have no scent. The sources give no mature height or spread for the whole plant.

Tall flower spikes appear in May and June. The spikes measure about 0.5–1.2 feet [0.15–0.36 metres] long. The small flowers have blue or green tones. Each node holds three to eight spikelets without stalks. Each hairy spikelet holds four to six florets. The fruit is a cream or tan grain called a caryopsis. The seed is small and hard to free from its covering.

Full sun suits this grass, though it also accepts partial shade. It grows in most soils but prefers sandy ground. Once established, it can cope with drought. NC State lists it for USDA zones 4–8. Reports on salt tolerance conflict, so coastal use is uncertain. Its wide root system helps bind inland sand dunes. That same spread makes it hard to keep within bounds. Plants For A Future warns that rhizomes can make it invasive. NC State calls it weedy and does not recommend garden planting. It lists high upkeep but no major pest or disease problems. Seed and division are both listed ways to raise plants.

People have used the seeds as a grain substitute in Russia. This use has included times of drought. Young underground shoots can be eaten raw and taste sweet. Plants For A Future lists no known hazards or medicinal uses. That does not establish safety for every person or pet. Researchers have crossed this grass with wheat to improve stress resistance. Trials have also explored its value as a perennial grain crop.