This summary of biological information on heart-podded hoary cress (Cardaria draba (L.) Desv.), lens-podded hoary cress (C. chalepensis (L.) Handel-Mazzetti), and globe-podded hoary cress (C. pubescens (C. A. Meyer) Jarmolenko) is the third in a series of contributions on plants that are weedy in Canada. The hoary cresses are weedy in open habitats, particularly in the Prairie Provinces and the interior of British Columbia.