Troubleshooting
Hollyhock problems — and how to fix them
Hollyhock (Althaea rosea) 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.
Hollyhock rust (Puccinia malvacearum)
The most common problem: orange-brown pustules on leaf undersides and yellow spots above, causing premature defoliation. Improve air circulation, remove infected leaves, and apply sulphur- or copper-based fungicide from early spring. Treat plants as disposable annuals and start fresh from seed each year to reduce inoculum.
Slugs and snails
Young seedlings and basal leaves are vulnerable to slug damage, especially in damp springs. Use slug pellets (ferric phosphate), copper tape, or nematode drenches. Raise seedlings under cover and harden off before transplanting.
Hollyhock weevil (Apion longirostre)
Larvae develop inside seed pods, destroying seeds before they ripen. Collect and destroy affected pods. For seed saving, hand-pollinate and bag flowers early.
Prevent hollyhock problems before they start
Most hollyhock issues are care-mismatch, not bad luck. Dial in the basics:
Hollyhock problems — FAQ
Why is my hollyhock hollyhock rust (puccinia malvacearum)?
The most common problem: orange-brown pustules on leaf undersides and yellow spots above, causing premature defoliation. Improve air circulation, remove infected leaves, and apply sulphur- or copper-based fungicide from early spring. Treat plants as disposable annuals and start fresh from seed each year to reduce inoculum.
Why is my hollyhock slugs and snails?
Young seedlings and basal leaves are vulnerable to slug damage, especially in damp springs. Use slug pellets (ferric phosphate), copper tape, or nematode drenches. Raise seedlings under cover and harden off before transplanting.
Why is my hollyhock hollyhock weevil (apion longirostre)?
Larvae develop inside seed pods, destroying seeds before they ripen. Collect and destroy affected pods. For seed saving, hand-pollinate and bag flowers early.