Laidback Gardener Tip of the Day

A Canna that Blooms Indoors? Why not?

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Canna ‘Maui Punch’

Every northern gardener knows that cannas (Cannageneralis) are summer bulbs. With their green, purple or variegated leaves reminiscent of those of a banana plant and their flowers in mostly bright colors like red, orange, yellow, pink, or white, not to mention bicolors, the canna is a plant built to impress. You plant them in the spring and they sprout, grow and bloom in the summer, then you dig up their thick rhizomes in the fall and store them dry in the winter in a frost-free spot. But how many gardeners know you can use cannas as houseplants and see them bloom all year long on your windowsill?

Dormancy is Optional

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Canna ‘Hello Yellow’ blooming in December … indoors of course!

Obviously, you do have to bring cannas indoors for the winter in a cold or even moderate climate: they are simply not frost tolerant. But you don’t have to put them into dormancy. It is perfectly possible to bring a canna in leaf or bloom indoors, just like you would bring  back indoors any houseplant you’d put outside for the summer, and keep it growing all winter. And if you have the right conditions, it will bloom over and over, all winter long!

This is possible because of a detail rarely mentioned in descriptions of how to grow cannas: that their dormancy is optional. In their native South and Central America, cannas mostly grow in swamps, ponds, and other poorly drained sites. But these wetlands are subject to periodic droughts, occasionally drying up completely. Sometimes this is an annual occurrence, but in others, the swamp can remain wet for years in a row before a drought hits.

Cannas have adapted to this by going dormant only when their soil dries out, sleeping underground in their thick rhizomes while waiting for the rains to return. Otherwise, as long as the soil remains moist, the plant will keep growing and blooming all year long. Unlike hardy bulbs like tulips and narcissus, where dormancy is mandatory (they will go dormant in the summer no matter what conditions you offer them), cannas don’t need a dormant period to grow and bloom. And no, blooming again and again with no period of dormancy doesn’t “tire them out”. As long as you continue to water your cannas and protect them from frost, they will continue to bloom on and on, even in winter.

The Right Conditions

It’s not at all that difficult to keep a canna growing and blooming on a windowsill indoors.

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Canna ‘Pretoria’

Start by bringing in a plant in full growth early in the fall, before the nights cool off too much. Indoors, offer as much sun as you can, such as a spot in front of a large south-facing window. The more sun, the better the bloom! Also, the room should be heated adequately, to 60°F (15°C) or above if possible. Most homes can easily offer that temperature range. Anything cooler will reduce or even eliminate flowering.

All that you have to do is to water the plant regularly, just like you would any houseplant. And for once, you can even leave the saucer filled with water: cannas are a swamp denizens, after all. If ever you do let your canna dry out too long, however, it will go dormant.

Each stem produces only 2 or 3 flower clusters. So when a stem has stopped blooming, cut it off at the base. Yep, the whole stem, leaves and all. This will give more space for the sprouts that appear regularly at the plant’s base to flower in their turn.

Since your canna is now growing and flowering all year, you’ll have to fertilize all year as well: use an all-purpose fertilizer at a quarter of the recommended rate in fall and winter and and at one-half the recommended rate in spring and summer.

You can keep your canna growing for years, even decades, indoors all year if you like or you can put it outdoors for the summer, which tends to stimulate even greater bloom, because sunlight is more intense outdoors and not filtered by passing through glass as it would be on a window sill.

A canna indoors? Why not? It works for me!

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

35 comments on “A Canna that Blooms Indoors? Why not?

  1. This is really helpful. When you say fertilize at 1/4 of the rate recommended – what does that mean – to do 1/4 frequency or to use 1/4 of the dose? Thanks

  2. I love this idea! We live in a climate with extremely long winters, and the cheery yellow, orange & red cannas would be a welcome burst of color by a window to the snowy landscape that stays “black & white” for 8 months a year. So glad I saw your suggestion!

  3. Betty 019 Lautner

    I bought a beautiful canna this past septemberI now have it indoors where it gets good sun. However, the edges of the leaves are turning brown. I’ve been cutting the stems back, but it is
    not looking happy….any suggestions as how to keep it healthy? It is approimately 46 inches high,
    has many stems still coming in, and in a 15 inch pot.

  4. Fabulous article! I recently purchased a variegated canna that simply blew my mind. It’s leaves look as though they are straight from a painter’s brush. The owner of the greenhouse saìd that they were growing these ‘not for sale’ plants for next spring sales. I was able to purchase one 😁 but was hesitant on proper indoor care.
    Thank you so much for this informative article! I hope to keep my canna happy and thriving indoors for years to come

    Cheers!

  5. Question!? I was going to chop it down to rhizome and just over winter the bulb. Now I’ve changed my mind and it’s been outside in a protected atrium. Still has green foliage and blooms. Can I change my mind and bring it in?

  6. Thank you for your article ! I bought one this summer not even knowing what it was. I potted it in a large pot. It was tiny and didn’t seem to grow.
    It was during the hottest summer month and I think I was watering it too much so I let it be and watered it once e a week. Within the 2nd month it became a behemoth of a plant ! It’s huge and bloomed in 3-4 places.
    Winter came upon us and I didn’t want to let it die so I brought it in a room where the windows are as big as walls so it’s getting quite a bit of sunlight.

    I took down your tips and will apply them throughout the winter and she will hopefully stay healthy and beautiful.

  7. Hello,
    I’ve lifted my cannas, have put them in green house, temperature there goes below (15°C) every winter , should I assume that this is not appropriated for the cannas to over winter as a house plant? , should cut back the stems and store them encouraging dormancy?
    what is the best way to store them ?
    Can I leave them to dry out in their pots with within the existing soil, at what temperature it will do fine?
    can they be exposed to light?
    Do I need to split/ divide them and any particular medium to store them in? .
    I would really appreciate your help.
    Thank you

    Gisele

    • At cooler temperatures, they won’t thrive. Just stop watering them and cut them back. You can leave them in their pots. Any temperature above freezing will be fine during dormancy. Being dormant, they won’t need light. By spring, they’ll be sprouting even if you didn’t water them all winter. That would be the best time to divide them if they look crowded. Then repot and start watering and up they’ll come!

  8. Thank you so much for your reply 🙂

  9. Could you co-plant them with bamboo – and grow indoors? Bamboo seems like they’d need more shallow planters. So, perhaps alongside? Would the callas appreciate the humidity that bamboo like?

    Thank you!

    • That’s a complicated question, as there are so many species of bamboo with such widely varying shapes, sizes, needs and habits that it’s almost impossible to generalize. Assuming you mean to do this indoors (subject of this article), right off the bat, few bamboo are really adapted to indoor conditions. Some are very dominant and could crowd the cannas out.

  10. Fran Gregson

    Thank you for a really interesting article. Cannas look such a tropical plant that they make you worry. I have been trying to decide what to do with my Cannas over the winter and having read your article I have decided I will bring them in and leave them in my conservatory. Hopefully they will continue to produce the most beautiful flowers over the winter.

  11. Diane J Teter

    I enjoyed your article. I planned on bringing my 2 containers of Canna Lilies in (and did). I decided to over winter them as if they were a houseplant. I have them under a broad spectrum grow light so they get enough “sun”. Good idea or bad? Thanks!

  12. I’m trying to winter mine over in the basement but they keep growing. Not going dormant! I’m not watering them but they are in their old pots.

  13. Geoffrey S Baldwin

    My neighbor allowed me to split off part of his plant. I potted them into 2 pots. The largest one is starting to flower indoors in a south facing window on Feb20th, 2021.

  14. Very interesting article – will definitely bring it in (it’s in a pot) this autumn – thanks

  15. John lappin

    If I decide to transfer to a larger pot for indoors what is the best compost I can use

  16. My daughter game me a Canna Bulb to plant outside but I decided to try it as an indoor plant. I put the rhizome in a pot 4 1\2″ tall by 6″ in diameter. It has only been about about 10 days and it’s grown about 6 inches tall! I’m worried now that the pot may not be large enough for it? Any comments will be welcome.

  17. Thank you so much for getting back to me so quickly. I will definitely repot it into a larger pot. I am very excited to see if grows into a beautiful plant?

  18. Beverly lambert

    I’m going to bring cannas from pond to indoors, can I repot to bigger pots now? I purchased slightly larger pots and a long tall sided tray to put the pots into. I was planning on keeping them wet like the pond over winter inside infront of south window. Will cutback stalks which are done blooming, there are a few new stalks which have started. Is this all ok as a procedure or is there something else I need to do? Thanks for any info. Your article made me deside to bring them in as houseplants til next summer in the pond again.

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