Bittercress

A couple of common species of weed which are difficult to distinguish between. One is Wavy Bittercress (Cardamine flexuosa), which is a short-lived perennial, whilst the other is Hairy Bittercress (Cardamine hirsuta), which is an annual or biennial. Both might be found in newly seeded areas or as weeds of lesser maintained amenity surfaces and lawns. They have small pinnate leaves arranged in a rosette pattern. The stem of Wavy Bittercress might be lightly hairy, whilst for Hairy Bittercress it might be hairless, but the with lightly hairy leaf stalks instead. They grow in damp, often shadier situations, although C. hirsuta may also be found in drier situations. C. flexuosa more limited to acidic soils, whilst C. hirsuta will also be found in calcareous soils. They flower from March-April to September, having very small white flowers, about 5mm or so in diameter, with 6 stamens on C. flexuosa and 4 stamens on C. hirsuta.