Troubleshooting
Drummond's Aster problems — and how to fix them
Drummond's Aster (Symphyotrichum drummondii) 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
Erysiphe spp. causes white powdery patches on foliage in humid, poorly ventilated conditions, especially in late summer. Space plants generously, avoid overhead watering, and cut stems to the ground in autumn to remove infected material.
Chrysanthemum lace bug
Corythucha marmorata sucks sap from the undersides of leaves, causing a mottled, stippled appearance and premature leaf drop. Inspect foliage from midsummer onward; treat with insecticidal soap or neem oil if infestations are heavy.
Self-sowing nuisance
In favourable conditions this species self-seeds prolifically and can become weedy. Deadhead spent flowers before seed sets, or thin seedlings in spring to prevent overcrowding.
Prevent drummond's aster problems before they start
Most drummond's aster issues are care-mismatch, not bad luck. Dial in the basics:
Drummond's Aster problems — FAQ
Why is my drummond's aster powdery mildew?
Erysiphe spp. causes white powdery patches on foliage in humid, poorly ventilated conditions, especially in late summer. Space plants generously, avoid overhead watering, and cut stems to the ground in autumn to remove infected material.
Why is my drummond's aster chrysanthemum lace bug?
Corythucha marmorata sucks sap from the undersides of leaves, causing a mottled, stippled appearance and premature leaf drop. Inspect foliage from midsummer onward; treat with insecticidal soap or neem oil if infestations are heavy.
Why is my drummond's aster self-sowing nuisance?
In favourable conditions this species self-seeds prolifically and can become weedy. Deadhead spent flowers before seed sets, or thin seedlings in spring to prevent overcrowding.