Overwintering Canna Lilies
Canna Lilies are tropical plants and don't like freezing weather. If your winter is cold enough to freeze the ground then you need to bring in your canna lilies over the winter.
Digging up the Canna Lilies
The stems of the Canna Lily come out of large rhizomes. Most of the rhizomes will be near the surface in the top 10 inches or less. Occasionally if they bump against a wall or the sides of the pot the rhizome will grow downward. it's quite easy to bruise or damage the rhizome so you need to dig carefully.
You can use a spade, or a garden fork. I've used garden trowel when I'm digging my Canna Lilies in large pots.
First step is to trim the stems about 6 inches above the root. This leaves a convenient handle.
If you have not used pesticides on your plants and you know your soil is safe, you can try tasting the inside of the stem. (It can be eaten in salads)
If I'm growing in a pot or a garbage can I invert the pot and tap the whole root ball out if I can.
If the Canna Lily is growing in the ground or a heavy pot then I carefully dig it out. I go all around the plant and carefully free it from the soil. Don't worry if you cut through a rhizome. Just put any piece aside.
The roots fill the pot quite tightly and I had to tap and pull quite hard
Next step is to free the rhizomes from the soil. I mostly use my hands. Go slowly and gently. You can trim the long fleshy roots but be careful not to damage or bruise the rhizomes.
Trim the Roots of the Canna Lily
When most of the soil is removed, trim the thick roots. You can also trim the stems a bit shorter.
If the rhizomes are very large you can carefully snap them in large sections. I do this every year because I usually need smaller roots for the pots.
The Canna Lily rhizome should be allowed to dry out for a few hours. Don't leave them in the sun and don't allow them to freeze. If the soil is very wet dry them till the soil left is almost dry. This is to prevent your Canna Lily from Rotting.
Prepare a large box and have some peat moss ready. I use rubbermaid containers but if I had wood boxes or bushel baskets they would work well. Put a layer of peat in the bottom at least 1 inch thick. Carefully put a layer of rhizomes on top of the peat and cover them with peat. Put more rhizomes in and cover them. it's important not to allow the pieces to touch otherwise they might rot. Cover the box with newspaper or plastic that has been slashed.
You want to keep your rhizomes from drying out completely but you don't want any condensation. DO NOT use the rubbermaid cover. Your roots will rot.
I've seen people wrap their roots in newspaper instead of peat moss.
That's it. Put your container in a DARK and cool place. It should be below 50 degrees F. otherwise the Canna will start growing too soon, or rot. I bring my plants in before the first frost and put them in the cold room in the basement. They should be cool but not freezing.
I'm sure that the roots could be kept in a refrigerator if you could spare the space.
During the winter, check on your Canna lily roots and make sure that they are not going mouldy because of too much condensation.
I've used this method overwintering my Canna Lilies for years. As soon as the weather warm up they start sprouting and it's a race to plant them. You can also start them inside in pots to give them an early start if you have a sunny window.
It is sometimes possible to overwinter your canna Lilies just by drying out the rizomes a bit and placing them in a loose pile in a bucket. This will work better if your roots are not damaged or bruised and if you have a nice cold dry room for them.
I try to be accurate and check my information, but mistakes happen.email me if you find mistakes, I'll fix them and we'll all benefit: Christine