10/14/2026
More cold preparation - time to collect your tender tu ers if you would like them to grow next year. Great tips here!
It's almost time to overwinter some of our summer favorites like canna, dahlia, and calla lily. Overall, the process to save tender perennials over winter looks the same for most species.
-Prune tender perennials back just before or just after the foliage is killed by frost in the fall. In Iowa, this is typically sometime between mid-October to early November, depending on the weather. If a killing frost has not occurred by early to mid-November, the process can be started as a frost is imminent.
-Carefully pull the bulbs (or tuber, rhizome, corm, etc.) out of the ground and remove any excess soil. Carefully label so you know which bulb is which in the spring.
-Allow bulbs to dry and then store them in a cool, dark, and dry location. Temperatures must not get below freezing. Cardboard boxes, plastic crates, paper bags, mesh bags, or containers of peat moss, shredded newspaper, sand, or vermiculite are all options for winter storage. Bulbs must be allowed to stay dry enough to remain dormant and free from moisture-loving mold or fungus, but damp enough not to dry out and shrivel up.
See specific recommendations for several widely grown tender perennials in this article: https://go.iastate.edu/RN0JGI
ISU Extension and Outreach - Agriculture and Natural Resources