The Hairy bitter-cress (Cardamine hirsuta) belongs to Brassiaceae (the Mustard family). It is an evergreen perennial herb that is native to Europe. This herb is naturalized widely in Japan. It grows in arid areas. The rosette-shaped basal leaflets are rounded, and the stem does not have many leaves. It has an earlier flowering season than other species, with flowers blooming around March, while the stems grow longer. The Japanese name "tanetsuke-bana" comes from the fact that the flowers bloom around the time when the seed rice is soaked in water to be sown in the nursery.
The distinguishing characteristics of this species are that the stem does not have many leaves, the basal leaves remain until the fruiting stage, the fruit is markedly obliquely upward, and the rosette shape is distinctive.