November is here and we have had our first frost of the season. This is a signal to plants in the garden that it is indeed time to stop growing and shut down for the winter. Plants grown from tubers that are not winter hardy such as canna lily and dahlia can be dug now and stored for planting again next season.
I harvest the tubers when the weather is predicted to be sunny for a couple of days. After digging the tubers I remove the stems and any excess soil. It is important to leave the tubers in the sun for a day or two to dry any soil that remains clinging to the roots.
Cannas seem indestructible and do not require any special care for overwintering protection. I pack them in brown paper bags (closed at the top), and they are perfectly healthy come spring! Dahlia tubers have a tendency to dry out and should be packed in layers using dry peat, wood shavings or the like.
I overwinter both canna and dahlia in a cool spot in the cellar. I also have canna growing in pots which I simply cut back to the pot and store in the cool cellar as well. Corms in these pots should be divided in the spring when new shoots begin to show.