Troubleshooting
Rock Cress problems — and how to fix them
Rock Cress (Aubrieta deltoidea) 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.
Straggly, open growth after flowering
Plants become untidy and bare at the centre if not cut back after flowering. Trim back hard by about two-thirds immediately after flowering in late spring to encourage compact, fresh growth and a second flush of blooms.
Powdery mildew
In dry summers or cramped, poorly ventilated positions, powdery mildew can coat leaves. Improve air circulation, water at the base, and apply a sulphur-based fungicide if severe. Hard pruning after flowering often resolves the problem.
Short-lived in rich, moist soils
Aubrieta thrives on neglect in lean conditions but declines in fertile, moisture-retentive soils. Improve drainage with grit and avoid feeding heavily. Plants typically live 3–5 years and should be regularly renewed from cuttings.
Prevent rock cress problems before they start
Most rock cress issues are care-mismatch, not bad luck. Dial in the basics:
Rock Cress problems — FAQ
Why is my rock cress straggly, open growth after flowering?
Plants become untidy and bare at the centre if not cut back after flowering. Trim back hard by about two-thirds immediately after flowering in late spring to encourage compact, fresh growth and a second flush of blooms.
Why is my rock cress powdery mildew?
In dry summers or cramped, poorly ventilated positions, powdery mildew can coat leaves. Improve air circulation, water at the base, and apply a sulphur-based fungicide if severe. Hard pruning after flowering often resolves the problem.
Why is my rock cress short-lived in rich, moist soils?
Aubrieta thrives on neglect in lean conditions but declines in fertile, moisture-retentive soils. Improve drainage with grit and avoid feeding heavily. Plants typically live 3–5 years and should be regularly renewed from cuttings.