Troubleshooting
Grefsheim Spirea problems — and how to fix them
Grefsheim Spirea (Spiraea cinerea 'Grefsheim') 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 sites
Saturated or poorly drained soils lead to Phytophthora root rot, presenting as wilting and browning foliage; always site in free-draining ground and avoid overwatering.
Reduced flowering from late pruning
This cultivar blooms on old wood; pruning in autumn or winter removes next year's flower buds — prune only immediately after flowering in late spring.
Aphids on new shoots
Clusters of green aphids can colonise soft new growth in spring; natural predators usually control them, but heavy infestations can be treated with insecticidal soap or neem oil.
Prevent grefsheim spirea problems before they start
Most grefsheim spirea issues are care-mismatch, not bad luck. Dial in the basics:
Looking for grefsheim spirea in general rather than its problems? Read the full grefsheim spirea care guide — light, water, soil and feeding.
Grefsheim Spirea problems — FAQ
Why is my grefsheim spirea root rot in wet sites?
Saturated or poorly drained soils lead to Phytophthora root rot, presenting as wilting and browning foliage; always site in free-draining ground and avoid overwatering.
Why is my grefsheim spirea reduced flowering from late pruning?
This cultivar blooms on old wood; pruning in autumn or winter removes next year's flower buds — prune only immediately after flowering in late spring.
Why is my grefsheim spirea aphids on new shoots?
Clusters of green aphids can colonise soft new growth in spring; natural predators usually control them, but heavy infestations can be treated with insecticidal soap or neem oil.