Culture
Easily grown in gritty or sandy, well-drained soils in full sun. Tolerates hot dry conditions. Also tolerates somewhat infertile soils. Propagate by seed or rosette-separation. Plants tend to decline in summer heat south of Zone 6. Cut back foliage after bloom to promote denser growth habit.
Noteworthy Characteristics
Arabis alpina, commonly known as mountain rock cress or alpine rock cress, is a mat-forming, tufted, procumbent, evergreen perennial of the mustard family that typically grows to 8-10” tall but spreads to 20” wide or more. It features loose spreading rosettes of toothed, obovate, gray-green basal leaves (to 2” long), shorter ovate stem leaves and tiny, 4-petaled, white flowers (each to 1/2” long) which bloom in spring. It is native to crevices of limestone rocks, along streams and in calcareous alpine meadows of Europe, Canada and parts of the northern U.S. from Maine to Wisconsin south to Tennessee.
Subsp. caucasica, sometimes commonly called wall rock cress, is best distinguished from the species by its sagittate stem leaves, longer petals and siliques (dry deniscent fruits). Subsp. name is in reference to the Caucasus Mountains where some plants in the subspecies are native.
Arabis caucasica is a synonym of Arabis alpina subsp. caucasica.
Genus name comes from Arabia where some plants in the genus are native.
Specific epithet comes from the Latin word alpinus meaning of mountains in reference to plant habitat.
'Schneehaube' SNOWCAP is a low-growing, mat-forming cultivar which reaches 7" tall with a 18" spread. The evergreen foliage is densely covered in clusters of white blooms during the spring.
Problems
White rust and downy mildew are common. Root rot may occur in overly moist or poorly drained soils. Watch for aphids.
Uses
Ground cover. Rock gardens, border fronts, dry banks or stone walls. Foliage is particularly effective climbing over rocks or cascading over walls.