Content Detail

Rock cress is a ground cover for small areas.  It works well in rock gardens, along retaining walls and as an edging plant. 

  • Family (English) Mustard
  • Family (botanic) Brassicaceae (formerly Cruciferae)
  • Tree or plant type Ground cover, Perennial
  • Native locale Non-native
  • Size range Small plant (6-12 inches)
  • Light exposure Full sun (6 hrs direct light daily)
  • Hardiness zones Zone 4, Zone 5 (Chicago), Zone 6, Zone 7
  • Soil preference Acid soil, Alkaline soil, Moist, well-drained soil
  • Tolerances Alkaline soil, Dry sites, Occasional drought
  • Season of interest early spring
  • Flower color and fragrance Fragrant, White
  • Shape or form Creeping
  • Growth rate Moderate

Size and Method of spreading:

Rock cress grows 6 to 12 inches high. It is a trailing-rooting ground cover.Trailing-rooting ground covers have trailing stems that spread out from a central root system. These stems spread out horizontally over the ground and can root where they come in contact with the soil. New shoots will be formed at the point where rooting occurs.

Native geographic location and habitat:

Native to the Mediterranean.

Leaf description:

The leaves that grow from the base of the plant are obovate and tend to lie flat. The leaves on the stems are borne alternately and are lobed.  All the leaves have some whitish hairs.

Flower description:

The white flowers are produced in early spring in loose clusters. Each flower has 4 petals and this is typical of the mustard family. The flowers are fragrant.

Fruit description:

Fruit are thin, pod-like silicles; not ornamentally important.

Plant care:

Rock cress needs full sun and a well-drained soil. Soil can be slightly acidic to alkaline This plant is drought tolerant and wet soils must be avoided. After flowering, shearing the plants will encourage them to remain neat and compact.

List of pests, diseases, and tolerances: 

Root and crown rot can be a problem in wet soils. Aphids and fungal leaf spots are occasional problems.  It is resistant to deer.

Snow Cap rock cress  (Arabis caucasica ‘Snow Cap’): 

Flowers more heavily than the species.

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