Rock Cress Plants: 4 Types of Flowering Rock Cress Plants

Rock cress—or rockcress—is the common name for plants in several different genera that fall into the flowering mustard family (Brassicaceae). These semi-evergreen, typically perennial plants thrive in rocky areas with full sun and good drainage, such as cliffsides in the Mediterranean and elsewhere throughout Europe, in parts of the Middle East and Asia, and across the United States.

Rock cress are flowering plants, and most rock cress flowers are white or a shade of purple, arriving in early spring to early summer. Since the common name might refer to any one of several dozen species, the variety in bloom size and color can be wide-ranging. Most share a thick foliage of vibrant green leaves. People consider some rock cress plants to be ornamental, others to be weeds.

There are several groups of plants that experts, gardeners, and the general public refer to as rock cress, totaling dozens and dozens of species. The following genera (or genuses) contain rock cress plants:

1. 1. Arabidopsis: Rock cress plants in this genus are primarily native to Europe. Species include Arctic rock cress, lyre-leaved rock cress, and sand rock cress. In the 1980s, a Russian crew grew Arabidopsis plants while in outer space.
2. 2. Arabis: The small white flowers of these plants can take root and flourish in rough terrain—even in small crevices in stone walls. Some rock cress plants in this genus include alpine rock cress, Armenian rock cress, and hairy rock cress. The Eastern European plant Arabis caucasica produces smooth white flowers that bees must pollinate so it can reproduce.
3. 3. Aubrieta: Mostly native to Europe and Asia, species in this genus are very hardy, able to grow in a variety of soil types and in full to partial sun. Perhaps the most well-known is Aubrieta deltoidea, also known as purple rock cress, false rock cress, or lilac bush. Other plants in this group include Lebanese rock cress and several cultivars.
4. 4. Boechera: Rock cress plants in this genus grow mainly in North America and might have white or purple flowers. Distinct species in this group include smooth rock cress, sicklepod rock cress, and Missouri rock cress.

Rock cress plants can be an exceptional perennial ground cover for any slope, rock wall, or container garden because they need limited maintenance and are self-sufficient in the proper environment. Although they are prone to aphids or flea beetles, rock cress plants are deer-resistant.

Plant rock cress seeds in alkaline soils in USDA Hardiness Zones 4–7. These plants are highly drought-resistant, but you should grow them in areas where they will receive direct sunlight and limited partial shade.

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