Rockress (Arabis)

Rockcress is a common name for *Arabis*, a genus of annuals and perennials in the mustard family. Species differ in size, foliage persistence, flower color, and habitat, so this genus-level record describes broad garden patterns rather than a single uniform plant. ## Form and Garden Use Many garden rockcresses are low, spreading or mat-forming plants with simple leaves and clusters of four-petaled flowers. The [Royal Horticultural Society’s genus profile](https://www.rhs.org.uk/plants/1430/arabis-alpina/details) notes that Arabis includes annuals as well as evergreen perennials and that flowers may be white, pink, or purple. These compact forms suit crevices, gravel beds, rock gardens, wall edges, and the front of sunny borders where drainage is sharp. ## Siting Light, soil, water, and winter tolerance depend on the species or cultivar. Alpine and Caucasian rockcresses generally perform best in sun and well-drained, gritty soil; avoid applying those preferences to every species without checking its identity. The [KPU Plant Database](https://plantdatabase.kpu.ca/Plant/arca) describes the Caucasian rockcress group as mounding and spreading, with a range of flower colors among cultivars. ## Maintenance Use the species or cultivar name to set spacing and care. For mat-forming perennial types, trim after flowering if growth becomes loose or woody, and keep crowns from sitting in wet soil through winter.