Canna Lilies

Canna lilies are gorgeous all Summer! But what to do with them at the end of the growing season?
Canna lilies can be pretty expensive to buy. After a beautiful display all Summer, I hate to just throw them in the compost heap.

You can save these beauties for next year with a few simply and easy steps. And the perfect part is they get bigger than they were this year! Cannas spread vigorously, forming clumps of thick, fleshy rhizomes held close to the soil surface. 

How to overwinter?

Mid-autumn and frosty temperatures will signal that it’s time to dig those rhizomes for winter storage. Let the frost visibly blacken canna foliage before you dig – usually in mid-to-late fall. The trick is to get them out of the ground before temperatures substantially drop and the ground freezes. Use a digging fork to gently lever the clump out of the ground. Separate the rhizomes with your hands. Be gentle, but do not worry if they break. The fleshy roots will dry up during storage, so again, handle carefully but don’t worry too much about breakage.

If they have been in garden soil, do not wash the rhizomes, as doing so invites disease problems during storage. Instead, remove the soil and lightly brush them off. However if they were located in a pond or water feature, you need to clean off the muck from the rhizomes.

Cut off the old foliage stalks 1-2 inches above the rhizome with a clean knife. Then, carefully inspect the rhizomes for rot or animal damage and discard those with signs of disease. If it’s a large rhizome, you can use a clean knife to cut off rotten or damaged areas to clean, white flesh. Remember, different cultivars of Canna look the same. If you’re digging several types at the same time, put them into large, labelled containers . Or you can use a permanent market to write the colors on the rhizomes. I label the colors with tags while the plants are growing so you know which color is which after they die off.

Place the sorted rhizomes into paper shopping bags. The paper bags will help maintain a good level of humidity without adding extra moisture.

Find a cool, dark space in a basement, crawl space, unfinished basement, unheated garage or deep cold frame that stays above freezing but below 55 throughout the winter. Non-fluctuating temperatures are best as they prevent early sprouting.

Avoid Outbuildings as they fall below freezing in the deep winter.

As temperatures increase and spring returns, inspect your rhizomes and throw away any that are rotten or diseased and if some are beginning to sprout in storage, lightly dampen with water to replenish resources. Cannas will be harmed by planting them in the garden too early, so make sure the temperatures are warmer.

Plant the rhizomes 3-4 inches deep in rich soil approximately 1’ apart with a small amount of balanced fertilizer. Lay the rhizome horizontally in the soil with any bud swellings (eyes) or new shoots pointing up. Water well and wait for your beautiful Cannas to return for another year of beauty!


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