I don't think I've gone a single year since starting this garden without growing cannas. They are a lazy gardener's dream, producing maximum "oomph" with minimal work. They look tropical, they grow fast, they love heat, they require little care, they have handsome foliage, and hummingbirds love their flowers. What more could we ask of any garden plant? Well, a bit of hardiness, for one thing. I'm sick of people telling me that their cannas overwinter in the ground when I've had no luck with them surviving any but the warmest winters. That means digging up the rhizomes and storing indoors, buying new ones in the spring, or bumming them off a gardening friend or family member. Let's see, which one of these requires the least effort?
Canna 'Musifolia' (August 2008)
Somebody always has canna rhizomes to give away. They produce rhizomes prolifically—the edible rhizomes are cultivated as a food crop in some tropical countries—and there's always more than enough to go around. Being a lazy gardener, I didn't dig up my own last year and of course none of them returned after such a cold winter. When my sister-in-law in Pennsylvania offered me some of her own I said sure, why not. Her photos showed the kind of canna I like: tall and natural-looking with small red flowers, probably the old heirloom Canna indica hybrid that goes around variously as Canna compacta, 'Robert Kent', 'Robert Kemp', 'Tiki Torch', and most charmingly, "outhouse canna". It was a busy spring for me, with a bit more travel than I like and a death in the family, so I didn't get them from her until early June. She gave me a cardboard box that had been sitting in her basement a bit too long, with slender, pale yellow shoots stretching up out of a plastic garbage bag of dry peat moss. But give cannas just a little bit of attention, and they'll grow.
I did finally get a few of the rhizomes in the ground, but there were just so many of them and I hate throwing perfectly good rhizomes away. So I left them sitting in the box on my back deck while I got distracted by other things. And they grew. Taking pity, I threw a bit of water on them, and they grew some more. And before long I had a beautiful clump of cannas growing ridiculously out of a little cardboard box. I wasn't even fertilizing them, and they looked perfectly healthy and happy. When they started blooming I was sufficiently shamed, and I finally got them potted into an old plastic pot that isn't really big enough, but it's bigger than the bag of peat moss and it will just have to do.
I already knew this, but it really brought home that cannas are excellent container plants. Even the largest cannas will grow in surprisingly small amounts of soil, ridiculously potbound, and while they may not reach full size, give them enough water and they'll grow and bloom. Heck, they're not even that particular about the watering; unlike many lush tropical plants (I'm looking at you, elephant ears) they won't shrivel up and turn crispy the first time they dry out a bit. I've grown them on my roof deck for several years, where they've taken a lot of abuse. The biggest problem is that they get top-heavy and blow over during storms.
Canna 'Musifolia' (August 2009)
Canna 'Russian Red' (September 2009)*
Now how about some hardy cannas I can leave in the ground? I would love to hear about cannas that overwinter in zone 7, especially some of the newer cultivars.
*The kitty is Sage, who we lost a year ago at the ripe old age of 19. I never even noticed her in this photo until just now.