How to Grow Rock Cress
Arabis caucasica
Arabis caucasica (Rock Cress) is a tough, low-growing evergreen perennial that smothers itself in white or pink flowers in early spring. Plant in full sun in poor, well-drained soil — it thrives in the gaps of dry stone walls and rockery crevices where drainage is perfect. Space 30 cm apart; it will spread to 50 cm. After flowering in late spring, trim lightly by about a third to keep it compact and bushy. Once established it is virtually drought-proof and needs no feeding. Fully hardy and maintenance-free except for the annual post-flowering trim.
Yearly Lifecycle
Care Essentials
Rarely needed. A light balanced feed after the trim in early summer helps produce fresh compact growth. Avoid rich feeding which makes plants lax and loose.
Watch For
- Arabis leaf miner
- Aphids on new growth
- Flea beetles (tiny holes in leaves)
- Downy mildew in wet springs
Companions
Aubrieta, Alyssum, Iberis, Saxifrage
Care Requirements
Light
Full sun essential
Arabis needs full sun for the densest flowering and most compact growth. In shade it becomes leggy and sparse with far fewer flowers. It is ideal for south-facing walls and sunny rockeries.
Watering
Drought-tolerant once established
Very drought-tolerant once established, especially when grown in walls or rockeries. Water only during prolonged extreme drought. Good drainage is more important than irrigation — waterlogged soil causes root rot.
Fertilizing
Minimal — light feed after trim only
Arabis thrives in poor soil and rarely needs feeding. A light balanced feed after the post-flowering trim in early summer is sufficient. Rich feeding produces lax, floppy growth with fewer flowers.
Pruning
Light trim after flowering keeps it compact
Trim by about one third immediately after flowering in late spring. This prevents legginess and keeps the plant neat. A harder renovation cut every few years revives woody or spreading plants.
Spacing
30 cm apart
Space plants 30 cm apart. Plants spread to around 50 cm and fill gaps in walls and rockeries. Closer spacing gives faster coverage; wider spacing allows each plant to cascade naturally.
Support
None needed
Arabis is low-growing and self-supporting. No staking or tying is required. It naturally cascades over walls and rocks without any support.
Growing Tips
Thrives in poor, gritty soil
Arabis prefers lean, sharply drained soil. Rich or moisture-retentive soil makes it lax and reduces flowering. Rockery crevices and the top of dry stone walls — where drainage is perfect — are ideal sites.
Trim after flowering to stay tidy
Cut lightly by about a third right after the flowers fade in late spring. Skip this and plants soon become leggy and sprawling with a woody, bare centre.
Early spring colour before most bulbs
Arabis flowers in late winter to early spring (DOY 70–100), often alongside Aubrieta and Alyssum, giving colour when the garden is otherwise bare.
Easy to propagate by division or cuttings
Divide established clumps in autumn or take softwood cuttings of non-flowering shoots after the trim. Both root readily and give free replacement plants.
Spacing & Planting
| Plant spacing | 30 cm |
| Row spacing | 35 cm |
| Mature height | 18 cm |
| Mature spread | 50 cm |
Space 30 cm apart. Arabis spreads to form low mats and cascades beautifully over walls and rockery edges.
