In the fall, you can store calla and canna plants for next year. Both are easy to overwinter; here’s how:
Overwintering calla lilies
These wonderfully colourful plants are from South Africa. In their natural habitat, they grow and flower during the wet season, going dormant during the following dry season. Fortunately, these bulbs are super easy to store over the winter. They have a tough outer coat and equally tough interior, making them less likely to shrink during storage. Give them what they like and they’ll multiply like crazy.
If you’ve grown them in pots, cut off the foliage and bring them in before frost. Chances are they’re probably wet, and the tubers will be plump and full of moisture. If they’re dug out at this stage, they can be easily damaged, and the wound can cause your tuber to spoil during storage. Bulbs and tubers need to ripen in order to survive dormancy. They will slowly dry out, forming thicker, tougher coats that don’t mind handling. They like a cool, dark (but not freezing) spot.
If you really must unpot them, carefully remove the soil and re-package them in vermiculite or ever-so-slightly moist peat moss before storage. But why bother? This is a messy job and it’s easy to accidentally mix them up if you’re keeping track of different varieties. They’ll actually store far better left alone in their pots. It’s what I’ve done successfully for years.
If you’re wondering where to put all your pots, fear not. You can stack them once they’ve dried out. The only thing to watch for are early sprouts growing as your callas wake up. (They don’t grow too well under another pot!) This shouldn’t happen until late winter, but sometimes they surprise you. Keeping them cool helps prevent them from sprouting too early.
Overwintering canna lilies
These popular plants have adorned Canadian gardens for generations. Their lush, tropical foliage and non-stop flowering are one of the highlights of summer containers and gardens. They’re native to tropical Asia where they flourish in the hot, wet growing season; some species reach seven feet (2 m). Here in Canada, where our winters are hardly hot and tropical, our shorter days and cooler weather signal that it’s time to move them indoors. They hate cold weather, so bring them in when overnight temperatures get into the low, single digits.
Canna virus – a bad news, good news story
The bad news: Unfortunately, there is a nasty virus in virtually all the big cannas grown in France, Israel, the Netherlands, Australia and the U.S., which are where almost all the canna sold in Canada come from. The disease was first identified years ago but little has been done to stop its spread. It has spread throughout the large nurseries of the world, with only a handful offering virus-free, healthy stock.
It’s known as yellow streak virus, and the name says it all. It first appears as faint yellow streaks in the foliage, increasingly spreading, eventually leading to distorted foliage and death. Like many plant viruses, it’s spread by sucking insects like aphids. There is no cure. Dispose of infected plants and surrounding soil in the garbage, not in your compost. The tragedy is you can’t see any evidence on the root or even early-season foliage. But the mature foliage in fall will show if the plant is infected, which leads me to…
The good news: Fortunately, the majority of cannas we grow aren’t bought. They’re traded, passed on, shared with family and neighbours or traded at horticultural societies. These have likely been around long before the virus even existed. If they’re healthy they’re probably fine. In fact, several canna nurseries and collections were saved by collecting healthy rhizomes from isolated virus-free gardens. So check your canna foliage carefully. If in doubt, throw them out.
Chop the foliage off a few inches above soil level. Cannas in containers can be brought indoors. If they’re in big pots, you’re better off lifting them as you would those growing in the garden. This requires some care because a healthy canna rhizome (root) will have grown a lot bigger over the summer.
Allow their plump, water-filled roots to ripen a bit before storage. Once ripened, you can remove any soil and place them in clear plastic bags filled with very lightly moistened (not damp) peat moss, storing the sealed bags in a cool, dark place. Check them from time to time to make sure they haven’t rotted (you’ll see a mushy area). Just cut this off, let the root dry off and re-store again in peat moss.