Troubleshooting
Sensation Mix Cosmos problems — and how to fix them
Sensation Mix Cosmos (Cosmos bipinnatus) 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.
Aphids
Common on soft new growth; a strong water jet or insecticidal soap spray is usually sufficient.
Stem lodging / flopping
Tall plants in windy sites may need staking; pinching young plants at 30 cm promotes bushier, sturdier growth.
Botrytis (grey mould)
In prolonged wet weather; improve air circulation and remove spent blooms promptly.
Bacterial wilt (Fusarium)
Sudden wilting of one or more stems; no cure — remove and destroy affected plants, rotate planting areas.
Thrips
Silvery streaking on petals; more problematic in hot, dry spells; treat with spinosad-based spray.
Prevent sensation mix cosmos problems before they start
Most sensation mix cosmos issues are care-mismatch, not bad luck. Dial in the basics:
Sensation Mix Cosmos problems — FAQ
Why is my sensation mix cosmos aphids?
Common on soft new growth; a strong water jet or insecticidal soap spray is usually sufficient.
Why is my sensation mix cosmos stem lodging / flopping?
Tall plants in windy sites may need staking; pinching young plants at 30 cm promotes bushier, sturdier growth.
Why is my sensation mix cosmos botrytis (grey mould)?
In prolonged wet weather; improve air circulation and remove spent blooms promptly.
Why is my sensation mix cosmos bacterial wilt (fusarium)?
Sudden wilting of one or more stems; no cure — remove and destroy affected plants, rotate planting areas.
Why is my sensation mix cosmos thrips?
Silvery streaking on petals; more problematic in hot, dry spells; treat with spinosad-based spray.