Troubleshooting
Dahlia 'Jazz' problems — and how to fix them
Dahlia 'Jazz' (Dahlia 'Jazz') 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.
Powdery mildew
Affects leaves in late summer; apply a preventative potassium bicarbonate spray and ensure adequate spacing.
Aphids
Soft growing tips are targeted; treat with insecticidal soap or introduce beneficial insects like lacewings.
Botrytis grey mould
Affects spent flowers and damaged stems in cool, wet spells; remove affected material promptly.
Earwigs
Feed on petals leaving ragged holes; use newspaper roll traps placed near plants overnight.
Tuber rot
Store lifted tubers in dry vermiculite or compost at 5-10°C to avoid rot during winter dormancy.
Prevent dahlia 'jazz' problems before they start
Most dahlia 'jazz' issues are care-mismatch, not bad luck. Dial in the basics:
Dahlia 'Jazz' problems — FAQ
Why is my dahlia 'jazz' powdery mildew?
Affects leaves in late summer; apply a preventative potassium bicarbonate spray and ensure adequate spacing.
Why is my dahlia 'jazz' aphids?
Soft growing tips are targeted; treat with insecticidal soap or introduce beneficial insects like lacewings.
Why is my dahlia 'jazz' botrytis grey mould?
Affects spent flowers and damaged stems in cool, wet spells; remove affected material promptly.
Why is my dahlia 'jazz' earwigs?
Feed on petals leaving ragged holes; use newspaper roll traps placed near plants overnight.
Why is my dahlia 'jazz' tuber rot?
Store lifted tubers in dry vermiculite or compost at 5-10°C to avoid rot during winter dormancy.