Animals become poisoned if they eat large quantities of the leaves in a short time. Both sheep and cattle may be poisoned by chokecherry. Although most losses occur when feed is scarce, a few animals seem to prefer this plant to other forage. Cattle sometimes are poisoned by eating leaves on branches trimmed from cultivated chokecherry trees. The toxic substance in chokecherry, hydrocyanic acid, is found principally in the leaves.
Leaves become less toxic as the growing season advances.
Chokecherry and arrowgrass both contain hydrocyanic acid. Other plants with cyanogenic potential include Sudan grass, Johnson grass, reed canary grass, white clover, birdsfoot trefoil, mountain mahogany, and Saskatoon service berry. Where and When It Grows Chokecherry grows in damp and fertile soil. It is found in thickets on hillsides and canyon slopes. It appears as a shrub or small tree among willows, poplars, and alders that grow along mountain streams.