- Name also: Rocketsalad, Rocket Salad, Salad Rocket, Garden Rocket, Roquette, Rucola, Rucoli, Rugula, Colewort, Arugula, Eruca
- Latin synonym: Eruca sativa
- Family: Mustard Family – Brassicaceae (Cruciferae)
- Growing form: Annual herb.
- Height: 20–50 cm (8–20 in.). Stem branching, glabrous.
- Flower: Corolla regular (actinomorphic), pale yellow, with brownish violet veins, approx. 2 cm (0.8 in.) wide. Petals four, approx. 2 cm (0.8 in.) long. Calyx erect, cylindrical, sepals four, 1 cm (0.4 in.) long, with tapering tip. Stamens 6, of which 4 long and 2 short, anthers yellow. Gynoeciem fused, a single carpel. Inflorescence an elongating raceme during fruiting stage.
- Leaves: Alternate, stalked. Blade pinnately lobed, terminal lobe large, with curved teeth. Upper leaves parallel to stem, lobeless.
- Fruit: Many-seeded (seeds in two rows) siligua, opening lengthwise, 2–3 cm (0.8–1.2 in.) long, thickest in middle (approx. 0.5 cm (0.2 in.)), parallel to stem, both halves with clear central vein and tip 7–10 mm (0.28–0.4 in.) long with seedless, flat beak. Stalk 3–5 mm (0.12–0.2 in.).
- Habitat: Rubbish tips, harbours, loading areas. Also a herb and salad plant.
- Flowering time: July–September.
Over the last ten years this Mediterranean plant has become very popular in Finland as an ingredient in salads to give them a litle extra kick. This of course means that the species is nowadays cultivated in Finland in gardens and professionally in fields. Some of it also manages to escape to the surrounding environment. Escaped rocket has a stronger flavour than the cultivated variety. According to the source of the information, rocket is either two species (E. vesicaria and E. sativa), two subspecies (E. vesicaria ssp. vesicaria and E. vesicaria ssp. sativa), or just one species, with the two different scientific names being synonyms for the same plant.
Another member of the Mustard family that is a close relative of rocket is common dogmustard (name also hairy rocket, Erucastrun gallicum), which is quite rare in Finland. Common dogmustard is more sparsely branched, has smaller flowers, is hairy, and its siliquae are longer and thinner than rocket’s.