Hoary cress, also known as whitetop, was probably introduced from Europe in alfalfa seed. It is a creeping perennial, which reproduces by seed and creeping roots. The extensive root system spreads horizontally and vertically with frequent shoots arising from the rootstock. It grows erect from 10 to 18 inches high and has a grayish-white-colored leaf. The flowers are white and numerous in compact flat-topped clusters which give the plant its name.
Hoary cress is one of the earliest perennial weeds to emerge in the spring, producing flowers in May or June. It grows in waste areas, cultivated fields and pastures, and is capable of vigorous growth. It is found commonly throughout Garfield County.