Troubleshooting
Caucasian Rock Cress problems — and how to fix them
Caucasian Rock Cress (Arabis caucasica) is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Invasive spreading
This is a very vigorous species that can swamp smaller plants in a rock garden. Trim back hard immediately after flowering each spring, and divide congested clumps every 2–3 years to keep growth in check.
Powdery mildew
Can affect foliage in hot, dry summers with poor air circulation. Improve airflow by cutting plants back after flowering. Resistant cultivars are available. A dilute neem oil or potassium bicarbonate spray can help in persistent cases.
Root rot in wet conditions
Heavy clay soils or prolonged winter waterlogging causes collar and root rot. Improve soil drainage before planting and avoid mulching directly against the crown. Wall crevice planting largely eliminates this risk.
Prevent caucasian rock cress problems before they start
Most caucasian rock cress issues are care-mismatch, not bad luck. Dial in the basics:
Caucasian Rock Cress problems — FAQ
Why is my caucasian rock cress invasive spreading?
This is a very vigorous species that can swamp smaller plants in a rock garden. Trim back hard immediately after flowering each spring, and divide congested clumps every 2–3 years to keep growth in check.
Why is my caucasian rock cress powdery mildew?
Can affect foliage in hot, dry summers with poor air circulation. Improve airflow by cutting plants back after flowering. Resistant cultivars are available. A dilute neem oil or potassium bicarbonate spray can help in persistent cases.
Why is my caucasian rock cress root rot in wet conditions?
Heavy clay soils or prolonged winter waterlogging causes collar and root rot. Improve soil drainage before planting and avoid mulching directly against the crown. Wall crevice planting largely eliminates this risk.