Bittercress may be small and short-lived but its ability to produce and disperse large amounts of seed makes it an exacerbating weed. Often introduced unwittingly on the compost of container plants, it can be hard to be rid of in a garden.
Related to the pretty cuckoo flower (Cardamine pratense), bittercress is a much drabber plant with insignificant white flowers and pinnate leaves. The arrangement of flowers and seed heads is typical of members of the mustard family (Brassicaceae).
Hairy bittercress (C. hirsuta) is the smaller of the two, sometimes growing just a few centimetres. Wavy bittercress (C. flexuosa) can grow strongly to reach around 50cm (18in) in height in damp conditions but is usually shorter in gardens.