Troubleshooting
Aster 'Professor Kippenburg' problems — and how to fix them
Aster 'Professor Kippenburg' (Symphyotrichum novi-belgii 'Professor Kippenburg') 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
The most common problem on novi-belgii asters. Spray with a baking-soda solution or potassium bicarbonate fungicide at first sign; ensure good airflow.
Aphids
Cluster on new growth. Control with insecticidal soap spray or encourage natural predators such as ladybirds.
Leggy habit in shade
Plant in full sun to maintain the compact form. Staking or the Chelsea chop (cutting back by one-third in early summer) helps prevent flopping.
Tarsonemid mites
Cause distorted, bronzed shoot tips. Remove affected growth; no effective chemical control is available to home gardeners.
Crown division decline
Clumps lose vigour after 2-3 years. Divide in spring, replanting only healthy outer portions to rejuvenate the plant.
Prevent aster 'professor kippenburg' problems before they start
Most aster 'professor kippenburg' issues are care-mismatch, not bad luck. Dial in the basics:
Aster 'Professor Kippenburg' problems — FAQ
Why is my aster 'professor kippenburg' powdery mildew?
The most common problem on novi-belgii asters. Spray with a baking-soda solution or potassium bicarbonate fungicide at first sign; ensure good airflow.
Why is my aster 'professor kippenburg' aphids?
Cluster on new growth. Control with insecticidal soap spray or encourage natural predators such as ladybirds.
Why is my aster 'professor kippenburg' leggy habit in shade?
Plant in full sun to maintain the compact form. Staking or the Chelsea chop (cutting back by one-third in early summer) helps prevent flopping.
Why is my aster 'professor kippenburg' tarsonemid mites?
Cause distorted, bronzed shoot tips. Remove affected growth; no effective chemical control is available to home gardeners.
Why is my aster 'professor kippenburg' crown division decline?
Clumps lose vigour after 2-3 years. Divide in spring, replanting only healthy outer portions to rejuvenate the plant.