What should you do with Cosmos plants in the autumn? Ours have grown very tall and are now falling over and looking past their best. Should we leave them to die down naturally, or should we cut them right down ourselves? We would like them to grow again next year! Thank you very much.
Caring for Cosmos
Certified GKH Gardening Expert
If you have an annual Cosmos variety, you can cut them back to the ground now. With perennials, it is best to let them keep at least some of their leaves until the leaves die by themsleves. You can cut them back part way now to improve appearance, and then cut them back all the way when the foliage dies.