Thursday, September 10, 2015

Cannas for the lazy gardener

CannasCanna indica 'Red Stripe' (September 2012)

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
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.

Cannas

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.

Canna

Canna

Canna

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.


deckCanna 'Musifolia' (August 2009)

Deck
Canna 'Robert Kent' (August 2015)

Canna_Russian_Red
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.

19 comments :

  1. I'll have to keep an eye out for that red stripe, it's beautiful just for the foliage alone!

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    1. Some of the cannas have darker leaves but I really like the subtlety of 'Red Stripe'. One of my absolute favorites.

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  2. I had a Musafolia and loved it. Didn't dig it up and it froze. The Red Stripe is nice and I love the Russian Red. Have to see if I can find it next year...

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    1. I would love to see more breeders developing cannas for their foliage. Too many have giant floppy flowers and absolutely horrendous foliage. I can't figure out why anybody would grow them.

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  3. In Rehoboth Beach. DE (zone 7b, a bit inland), red leaved cannas hardy on south side of house. Variegated ones are marginally hardy (survive every other year). Basjoo bananas for years, recently lost red stemmed banana after two years inground. All hardy palms toast here, in-town ones survived.

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    1. Thanks for the update, it's been a year since my last trip to Rehoboth Beach and I need to check out some of the plantings I've seen in previous years.

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  4. That is an amazing clump growing out of a cardboard box! I have a yellow-flowered form of the wild Canna indica grown from seed collected in New Orleans. I can only ever get the seeds to germinate by throwing them in a garden bed and waiting for them to pop up during the hottest part of the summer. Once they get going, though, they grow rapidly and flower within a few months. For me they will not survive in the ground either. Not surprising in New England, of course, but I know of a few gardens here in Cambridge where they not only survive but flourish, and I have even seen gardens in metro Detroit (!) where they are left to their own devices and growing rampantly. My guess is that in all those places they are right by some heating ducts or something that keeps the ground from freezing and gives them a boost of extra warmth in the spring.

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    1. I often find cannas growing up from seed in my beds and it's amazing how fast they grow. This year, I have what I'm fairly certain is 'Musifolia' growing from seed, even though it's been 2 or 3 years since I've grown that one. Castor beans (Ricinus communis) and Manihot grahamii have similarly hardy seeds, although the plants themselves aren't hardy here.

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  5. A piece of Pretoria canna accidentally stayed in the ground in Alexandria's winter and came up the next year. I tried leaving them in the next year and they all perished. Never again. I wish the one I have in the ground looked as good as the one you have growing in the bag.
    Ray

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    1. The same cannas, planted in the ground, did rather poorly due to the drought this summer. My container plants get more regular water than my plants in the ground. I know that some cannas are relatively hardy because I see them coming up around DC every spring--one of these days I'll find a reliably hardy one.

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  6. I noticed your last two posts had "lazy' in the title.
    Ray

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    1. Heh, I wondered who would notice that. Didn't realize it myself until after I had posted this one--and I was too lazy to come up with a different title!

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  7. I planted Bengal Cannas against the wall of a client's house years ago. In zone 5 - and they come back every year!

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    1. Growing up in Buffalo (zone 5) I had a neighbor who had a beautiful clump of gladiolus planted up against the house that came back year after year. That zone, just a few inches wide, can often support many plants that are otherwise not hardy.

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  8. We have no trouble overwintering cannas in the ground down here, but we do have a devil of a time with canna leaf rollers. Unless you are prepared to keep them regularly sprayed with Bt, or sell your soul and use a systemic, they will be made very ugly by the critter. It has gotten so bad that few gardeners are planting them anymore.

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    1. No leaf rollers yet, knock on wood! And no japanese beetles either, their other scourge. I do have trouble with slugs; the giant spotted ones will crawl up the stems to eat the tender emerging leaves, and when they unroll it leaves a neat row of holes right across the leaf.

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    2. The trick with Bt spray is to use it a few days in a row when air is still before you actually see damage on leaves....this kills off the little leaf munchers pretty well..and sends out same message to the June bugs too...zone six here so I have to dig up every fall these huge root systems...break up easy for next years use...I leave the rest to freeze in the grounds tilling under come spring....

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  9. i noticed the manihot in the first pic of the red stripe, what do you do with that in the winter? can it be cut back? I am trying to figure out what to do with mine since its my first year with it.

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  10. Hi John. I am very interested in growing cannas and other plants that are not hardy for my zone 7a/b (East Tennessee) by installing thermal wire about 3" under the soil thru out the growing area. Also, want to try using thermal tubing under the soil and pumping heated anti-freeze thru them. Hopefully I can keep the ground warm enough that most of the plants survive the winter with proper mulching and coverings.

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