Diplotaxis tenuifolia aka Perennial Wild Arugula

Diplotaxis tenuifolia is wild rocket, also called perennial wall-rocket. It belongs to the mustard family, Brassicaceae. Its native range spans Europe and the Mediterranean region. NC State also lists western Asia and northern Africa. This perennial grows fast and can form leafy clumps. Gardeners can also grow it as an annual crop. It has escaped gardens in parts of North America. There, it sometimes grows on disturbed ground.

Plants reach about 0.5–2 feet [0.15–0.6 metres] tall. RHS describes leafy plants around 0.7 feet [0.2 metres] tall. Its listed upper height is 1.6 feet [0.5 metres]. Spread reaches about 1–2 feet [0.3–0.6 metres]. Plants may stand upright or creep, with several stems. The smooth stems are green and lack scent. Narrow green leaves grow alternately along them. Each simple leaf has lobed edges and a pointed tip. The leaf base forms a wedge. Some leaves bear hairs beneath, and plants shed their foliage.

Yellow flowers appear in summer, with NC State specifying late summer. Each flower has four petals and a cup-like shape. Flowers can stand alone or form rows around stems. Hoverflies visit them and help with pollination. The brown fruit is a capsule under one inch [0.025 metres] long. When ripe, it splits into two halves. Both leaves and flowers provide food as well as garden interest.

Grow wild rocket in sun or partial shade. It prefers moist soil that drains well. Sandy soil suits it, but other soil types also work. It tolerates poor ground and a broad pH range. It withstands drought and heat, though shelter from intense heat helps. Protection from frost can also help. RHS rates it H3 for mild UK sites. NC State lists USDA zones 5a–9b. These sources give different impressions of its cold tolerance. Plants can reach full size within a year.

Use it in food gardens, pots, or small groups. Pick leaves from spring through fall for a peppery crop. Eat them raw in salads or cook them lightly. The stalks have a crisp bite; flowers also suit salads. NC State describes all plant parts as edible. Repeated sowings help maintain a steady leaf supply. Sow seeds after the last frost, about 0.016 feet [0.005 metres] deep. Plants need no routine pruning and little upkeep. Flea beetles, slugs, and snails may damage them. RHS reports few disease issues; NC State lists no major problems.