- Family: Mustard Family – Brassicaceae (Cruciferae)
- Growing form: Annual or biennial herb.
- Height: 20–40 cm (8–16 in.). Stem upper part branched, glabrous, bluish green.
- Flower: Corolla regular (actinomorphic), pinkish, approx. 0.5 cm (0.2 in.) across; petals four, 2–3 mm (0.08–0.12 in.), long. Sepals 4. Stamens usually 6 (sometimes 4). Gynoecium fused, a single carpel. Inflorescence an elongating raceme in fruiting stage.
- Leaves: Alternate. Blade compound-lobed, uppermost leaves almost pinnately lobed–pinnate, sometimes entire.
- Fruit: Two-seeded, elliptic, flat, tip broadly winged, with notched tip, grey, approx. 6 mm (0.24 in.) long silicula. Stalk quite erect, 5–8 mm (0.2–0.32 in.) long.
- Habitat: Rubbish tips, wasteland, roadsides, bird-feeding places, yards, gardens.
- Flowering time: June–August.
Genus Cress’s 200 species grow in temperate and subtropical climates, as well as tropical mountain ranges around the world. As indigenous wild plants they can usually be found in mountain meadows, rocky outcrops and salty ground, but many species have also made themselves at home around inhabited, cultivated areas. Garden cress is probably native to Egypt and the Middle East: it is an old cultivated plant that has however spread far and wide with people and made itself at home in civilised countries outside its natural habitat. Garden cress is eaten as a spring green in salads, and its seeds are used to make mustard. The Mustard family includes a whole group of plants that are important to humans for nutrition, and many feral species’ leaves are good to eat early in the season. Species in the family usually contain chemical repellents to defend themselves against attackers, so they have adapted well as plants for human consumption. Many cultivated varieties that have been bred for a long time have become completely dependent on humans: they could no longer survive without fertilizer, insecticide and fences to keep herbivorous attackers at bay. Uncultivated plants such as garden cress often visit Finland only shortly due to our short single growing season and harsh winter.
Garden cress that grows in Finland as an unestablished garden escape or casual alien is most easily found in the centre of inhabited areas, in half-forgotten places and sites with a lot of traffic. Garden cress doesn’t catch the eye as it grows among other weeds in its habitat. For a plant that follows humans, its lack of demands are a curse as well as a blessing: nobody bothers to pick such an undemanding plant, and it is hardly noticed from above. To the botanist garden cress is a nice and exotic surprise. To the sharp-eyed classifier genus Cress can offer a lot of new experiences: even representatives of South America have been found growing wild in Finland.