Arabis alpina aka Alpine Rockcress

Arabis alpina is an evergreen perennial in the mustard family. Its common names include mountain rockcress and alpine rock cress. It grows across Europe, Asia, Africa, and North America. It is also native to Britain and Ireland. Wild plants grow in rock cracks and on mountain scree. They also grow beside streams and in lime-rich alpine meadows.

This low plant forms tufts and mats of spreading stems. Garden plants reach about 0.7–1 foot [0.2–0.3 metres] tall. Their spread can reach 2 feet [0.61 metres]. RHS gives a broader height range, reaching 1.6 feet [0.5 metres]. Loose rosettes hold toothed leaves shaped like broad, reversed eggs. The basal leaves reach about 0.17 feet [0.05 metres] long. Stem leaves are shorter and oval. Sources describe the foliage as mid-green or grey-green. Small white flowers have four petals and a scent. They bloom in spring, with Missouri Botanical Garden listing April–May.

Grow this plant in full sun with good soil drainage. Gritty or sandy soil suits it, including soil with few nutrients. RHS also lists chalk, loam, and clay as suitable soils. It accepts acid, neutral, and alkaline conditions. It tolerates drought, dry ground, and shallow, rocky soil. Yet plants may decline in summer heat south of USDA Zone 6. Missouri Botanical Garden lists USDA Zones 4–7; RHS rates it H6. Trim the foliage after bloom to help keep growth dense. Raise new plants from seed, divisions, or summer softwood cuttings.

Its low growth suits rock gardens, dry banks, and border edges. Stems can spread across rocks or trail over stone walls. It also serves as ground cover on slopes. RHS lists gravel gardens and containers among its uses. The flowers provide a spring display and suit cutting. Missouri Botanical Garden also lists resistance to deer. These traits make it useful in sunny sites with limited soil depth.

Missouri Botanical Garden reports no major pest or disease problems. Still, wet or poorly drained soil can cause root rot. Other risks include downy mildew, white rust, and virus diseases. Aphids, flea beetles, and arabis midge may also attack plants. Plants For A Future lists young leaves and flowers as edible. Both have a cress-like taste and suit raw or cooked use. That source records no known hazards or medicinal uses.