Troubleshooting
Sunflower problems — and how to fix them
Sunflower (Helianthus annuus) 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.
Toppling stems
Stake tall single-stem varieties; shallow root systems in wind.
Birds eating young seedlings
Cover with cloches until 15 cm tall.
Squirrels on ripening heads
Cover with mesh bags as petals drop.
Powdery mildew on lower leaves
Normal in late summer; improve airflow and remove worst leaves.
Sclerotinia head rot
Brown mushy heads; remove and dispose, rotate planting site.
Prevent sunflower problems before they start
Most sunflower issues are care-mismatch, not bad luck. Dial in the basics:
Sunflower problems — FAQ
Why is my sunflower toppling stems?
Stake tall single-stem varieties; shallow root systems in wind.
Why is my sunflower birds eating young seedlings?
Cover with cloches until 15 cm tall.
Why is my sunflower squirrels on ripening heads?
Cover with mesh bags as petals drop.
Why is my sunflower powdery mildew on lower leaves?
Normal in late summer; improve airflow and remove worst leaves.
Why is my sunflower sclerotinia head rot?
Brown mushy heads; remove and dispose, rotate planting site.