Arabis spp.

rock-cresses

Brassicaceae Temperate Northern Hemisphere

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant Container Friendly

Native to North America

SunFull Sun

WaterLow · drought-tolerant

HardinessZones 3–7

Overview

Arabis spp. is a genus of roughly 100 species of annual, biennial, and perennial herbs in the family Brassicaceae, distributed across the temperate Northern Hemisphere and on mountains farther south. Most cultivated species are low, mat- or cushion-forming perennials 4-12 in (10-30 cm) tall and 12-18 in (30-45 cm) wide, spreading by trailing stems that root as they go. The leaves form basal rosettes of gray-green, often hairy, spoon-shaped blades 0.5-2 in (1-5 cm) long, with smaller clasping leaves up the flowering stems. In early spring the plants carry loose racemes of four-petalled flowers, each 0.3-0.6 in (8-15 mm) across, in white, pink, or purple. The cross-shaped flowers are typical of the mustard family and give way to long, narrow seedpods called siliques. Rock-cresses grow in rocky, fast-draining sites such as walls, screes, and gravel, and tolerate poor soils and drought once established. They decline in heavy, wet ground and can rot at the crown through humid summers. Many species self-seed and naturalize where conditions suit them.

Native Range

Arabis spp. is native across the temperate Northern Hemisphere, including Europe, North Africa, temperate Asia, and North America, extending onto tropical mountains. Species grow on cliffs, rock outcrops, screes, and dry grassland, often on limestone.

Suggested Uses

Arabis spp. is grown in rock gardens, on dry stone walls, along path edges, and in gravel and scree plantings. Mat-forming species are used as spring-flowering groundcover on banks and between paving. The early flowers draw bees and other pollinators.

How to Identify

Identify Arabis spp. by basal rosettes of gray-green, often hairy spoon-shaped leaves and erect stems bearing four-petalled white, pink, or purple flowers in spring. The cross-shaped flower and the long, slender seedpod, or silique, mark it as a member of the Brassicaceae. Mat-forming species root along trailing stems to form spreading cushions.

Appearance

Size & Dimensions

Height4" - 1'

Width/Spread1' - 1'6"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~5 weeks

Spring

Most Arabis spp. species flower in early to mid-spring, generally March to May, with bloom lasting four to six weeks. Flowering begins as temperatures rise and continues until early summer heat ends the show. Sheared plants sometimes produce a lighter second flush.

Detailed Descriptions

Flower Description

white, pink, or purple

Foliage Description

gray-green

Growing Conditions

Sun Requirements

SunFull Sun

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

sand rocky loam chalk

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow Arabis spp. in full sun in gritty, sharply drained soil of low to moderate fertility, since rich or wet ground shortens its life. Plants take drought, wind, and poor rocky soils once established and settle well on walls, rock gardens, and gravel. Water sparingly and let the soil dry between waterings, because crowns rot in standing moisture. In humid-summer regions, open spacing and free air movement lower fungal problems. Shearing plants back by half after flowering keeps the mats dense. Most species are hardy in USDA zones 3-7 and take no winter protection.

Pruning

Shear Arabis spp. back by one-third to one-half soon after flowering to remove spent stems and keep the cushion compact. Plants left unsheared grow open and woody at the center within a few years. Old, bare clumps are commonly renewed from cuttings or self-sown seedlings.