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Bittercresses (Cardamine spp., Brassicaceae) are the most common cool-season weeds in nurseries, but can persist and spread year round in shaded, moist environments. There are several bittercress species in container production, the most common of which is flexuous bittercress (C. flexuosa). Plants form a basal rosette of leaves. Flowers are white and form small, cigar-shaped fruit. Plants are prolific seed producers and seeds are forcefully expelled 3 to 6 feet. Freshly-shed seed have no dormancy. Seedlings are numerous, small, and are time-consuming to hand remove. Plants often harbor whitefly and mites and have been implicated as alternative hosts for some nursery crop diseases. Do not let plants go to seed. Control bittercress around the property to prevent spread. Inspect all new plant materials for infestations of this weed. Bittercress is well controlled by available preemergence herbicides but due to its prolific seed production and continuous germination it continues to be one of the most common weeds in container nurseries. [TOP]
