Hoary Cress · Cardaria draba (L.) Desv. · (aka whitetop, whiteweed, and perennial peppergrass) is a perennial Forb that originated in Eurasia. It flowers from April through June, and reproduces through rhizomes and seeds.
Found in pastures, smallgrain fields, roadsides, ravines, meadows, and waste places, livestock will graze hoary cress, but only when better forage is unavailable. Its seed are eaten by ground-foraging birds. The foilage of hoary cress contains a substance causing irritation to mucous membranes of animals. It is only a problem when forage is in short supply.
Hoary cress is an aggressive weed that often forms large, dense stands which are difficult to eradicate or control.