HCN may be produced by a few other plant species. Wild cherry trees produce toxic levels. Problems with wild cherry poisoning occur most often when animals consume wilted leaves after trees have been damaged by storms or pruning. The amount of dhurrin is higher in young plants than in older ones. The dhurrin content of leaves is higher than that of the stems.
Upper leaves contain more than the lower ones.
Dhurrin concentration decreases as the plants become taller and more mature. Usually, sorghum-type plants 18 to 24 inches tall are less likely to contain high concentrations of the toxin. Immature plants and re-growth following haying or grazing contain the highest levels. Drought and frost are closely associated with high levels of dhurrin. Plants growing under stress and those that have received nitrogen rates above 75 pounds per acre in one application may result in more toxin.