Troubleshooting
Coreopsis 'Moonbeam' problems — and how to fix them
Coreopsis 'Moonbeam' (Coreopsis verticillata 'Moonbeam') 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.
Root rot in wet soils
The primary cause of plant death. Ensure excellent drainage; avoid clay-heavy or waterlogged sites, especially in winter.
Flopping stems
Caused by too much shade or too-rich soil. Grow in full sun in lean soil; deadhead regularly to encourage fresh upright growth.
Aster yellows (phytoplasma)
Causes distorted, yellowed growth. No cure; remove and destroy affected plants immediately to prevent spread via leafhoppers.
Crown decline
Older clumps may die out in the centre after several years. Divide in spring every 3-4 years to rejuvenate.
Aphids
Occasionally infest new shoot tips. A strong jet of water or insecticidal soap is usually sufficient to control them.
Prevent coreopsis 'moonbeam' problems before they start
Most coreopsis 'moonbeam' issues are care-mismatch, not bad luck. Dial in the basics:
Coreopsis 'Moonbeam' problems — FAQ
Why is my coreopsis 'moonbeam' root rot in wet soils?
The primary cause of plant death. Ensure excellent drainage; avoid clay-heavy or waterlogged sites, especially in winter.
Why is my coreopsis 'moonbeam' flopping stems?
Caused by too much shade or too-rich soil. Grow in full sun in lean soil; deadhead regularly to encourage fresh upright growth.
Why is my coreopsis 'moonbeam' aster yellows (phytoplasma)?
Causes distorted, yellowed growth. No cure; remove and destroy affected plants immediately to prevent spread via leafhoppers.
Why is my coreopsis 'moonbeam' crown decline?
Older clumps may die out in the centre after several years. Divide in spring every 3-4 years to rejuvenate.
Why is my coreopsis 'moonbeam' aphids?
Occasionally infest new shoot tips. A strong jet of water or insecticidal soap is usually sufficient to control them.