Canna bulbs, or rhizomes, grow into stunning canna lilies, blooming in shades of bold oranges, reds, pinks and yellows. The vibrant sunset color palette of these perennial flowers show their heads from mid-summer up until the first frost, adding a flare of tropical energy to your yard for months on end.
However, as the winter season sets in, canna lilies won't feel quite so vivacious. In fact, if the temperatures drop too low and you haven't overwintered your canna bulbs, they may not survive to see your flower beds again.
You can leave canna lily bulbs in the ground, but only under certain conditions and within specific plant hardiness zones. Here, plant experts break down the specifics to ensure your cannas continue to thrive.
Can I leave canna bulbs in the ground over winter?
Since canna lilies are perfect for tropical garden ideas and typically thrives in warm conditions, the winter can be a struggle. If you live in an area which has relatively mild winters, the bulbs are capable of surviving in the ground in a somewhat dormant state. However, this is something that will need to be looked into prior to planting as in many parts of the world the bulbs won't survive.
Ofra Gaito, CEO of Verdant Lyfe Plant Shop, says, 'Canna bulbs shouldn’t stay in the ground in most places during winter, especially if it gets cold enough to freeze. They are not frost-tolerant, so if you live in a region where the winter temperatures dip below freezing, it’s generally a good idea to dig up the canna bulbs in the fall to prevent them from being damaged by cold weather.'
Leaving canna bulbs in the ground when it's too cold outside can lead to the bulbs freezing or beginning to rot, so be sure to add lifting them from the ground (if necessary) to your fall gardening checklist. Both of these things will result in the canna bulbs no longer being viable to grow.
What temperatures can canna bulbs withstand?
Andrew Bunting, vice president of horticulture at the Pennsylvania Horticultural Society, says, 'Canna rhizomes will remain hardy in the garden until temperatures get down to approximately 15 degrees F. To aid in them overwintering, you can add a pile of mulch to cover the canna rhizomes for the winter, though once temperatures get too low the rhizome will freeze which can result in irreparable damage.'
Alexandra Moreno, a landscaping designer and tropical plant expert, adds, 'Among tropical flowering plants, cannas are among the most cold-hardy species, with yellow flowering varieties being the absolute toughest and cold-hardiest.
'If you're in a US hardiness zone lower than 7, it is recommended to dig up the rhizomes and store them until the weather warms up again.'
If you're unsure what the temperature is in your yard, we recommend looking into purchasing an outdoor thermometer like the MUMTOP thermometer and rain gauge from Amazon. Combine this with a plant meter, also from Amazon, which will tell you the moisture of your plant's soil, its humidity level and more, and you'll be as in-the-know as possible about your plants' environment.
Once canna lilies reach the end of their blooming cycle, they can benefit from a good trim to stay healthy. Learning how to prune canna lilies is simple, but also the key to keeping them alive for years to come.
