Hello everyone, I am a new to gardening. I planted a few cosmos and one of them looks like it might canker disease or it could be something else. I've read up to terminate the plant ASAP. But the damage is only on the flower not on the stems nor at the root. Any suggestions as to what I can do?I have 3 Cosmo plant planted on the same pot. Should I also remove all of them if the flower is infected?

Hi Erika. Canker can attack your Cosmos once the flowers have bloomed, but it causes dark brown scab-like formations on the stems rather than on the blooms.

Welcome to the site.

Welcome, Erika.


I have seen something similar on flowers during periods of drought, but don't know what is causing that on your Cosmos.

If it's only on the flowers, it's probably sunburn or windburn. Don't worry about it.