Key takeaways
- Start rhizomes in pots indoors in March or April for earlier flowers
- Plant out after the last frost, from late May in the south to early June in the north
- Choose the sunniest, most sheltered spot you have
- Feed weekly with a high-potash liquid feed from early summer
- Lift rhizomes once frost blackens the leaves and store them frost-free
Cannas bring a touch of the tropics to a UK garden. Their big paddle-shaped leaves come in green, bronze or striped, and their bright flowers keep going from July until the first frost. They’re easier than they look, as long as you give them warmth, food and a frost-free winter.
Cannas grow from rhizomes, thick fleshy roots that store energy. They’re tender, so in most of the UK you plant them out after the last frost and lift them again in autumn. This guide covers buying, starting, planting, feeding and storing them, plus the best varieties to try.
Choosing canna rhizomes
Buy rhizomes in late winter or early spring, or potted plants from late spring. Pick firm, plump rhizomes with several visible buds, called eyes. Avoid any that are soft, shrivelled or have dark patches.
Bigger rhizomes with more eyes make bigger plants that flower sooner. Cheap, small pieces may take a season to build up. Potted plants cost more but give you a head start.
Look for firm rhizomes with plump pink buds. Avoid any with soft or dark patches.
Starting canna rhizomes indoors in spring
Starting cannas indoors gives you flowers weeks earlier. The UK summer is short, and rhizomes planted straight into cold soil in late May may not flower until late summer.
Pot rhizomes up in March or April and keep them warm. You’ll have sturdy plants ready to go out by late May.
In March or April:
- Pot each rhizome into a 2-3 litre pot of multipurpose compost.
- Lay it flat with the buds facing up, under about 5cm of compost.
- Water once, then keep the compost only just moist until shoots appear.
- Keep them warm: a heated greenhouse, propagator or bright windowsill in a warm room.
Shoots usually appear within a few weeks. Once they’re growing well, water more and give an occasional liquid feed. In May, harden them off for a week or two by putting them outside by day and bringing them in at night. Our guide to hardening off bedding and half-hardy plants explains how.
When and where to plant cannas outside
Plant cannas out once the risk of frost has passed. In southern England that’s usually late May. In northern England and Scotland, wait until early June. Cold, wet soil makes them sulk and can rot the rhizomes.
Give them the sunniest, most sheltered spot you have, ideally in front of a warm wall. Cannas in shade grow slowly and flower little.
Prepare the soil by digging in plenty of well-rotted manure or garden compost. On heavy clay, add some grit so water drains away. Plant rhizomes or potted plants about 5-10cm deep. Space tall varieties about 60cm apart and shorter ones about 40cm apart. Water well and mulch to hold moisture.
Cannas look best in groups of three or five of one variety. A single plant can look a bit lost.
Bananas behind, cannas in the middle and dahlias in front make a classic tropical-style border.
Feeding and watering cannas through summer
Cannas are hungry and thirsty. Treat them a bit like tomatoes.
- At planting: mix a slow-release fertiliser or a handful of fish, blood and bone into the soil.
- From early summer: give a high-potash liquid feed, such as tomato feed, every week.
- In pots: feed every week without fail, as watering washes food out.
- In September: stop feeding as growth slows.
Water well in dry spells, especially in the first few weeks after planting. Pots need watering every day in hot weather.
Deadhead spent flowers by snapping them off, and new buds will follow. When a whole stem has finished flowering, cut it back to the leaves below. Our guide to deadheading flowers covers the basics.
The best canna varieties for UK gardens
There are lots of lovely cannas. These are popular, widely sold and reliable.
| Variety | Leaves | Flowers | Rough height | Good for |
|---|---|---|---|---|
| Tropicanna (‘Phasion’) | Striped orange, pink and green | Orange | 1.5m | Borders and big pots |
| Wyoming | Bronze-purple | Orange | 1.8m | Back of the border |
| Black Knight | Bronze | Deep red | 1.5m | Dark colour schemes |
| Stuttgart | Green and white variegated | Apricot | 1.8m+ | Light shade, as leaves can scorch |
| Picasso | Green | Yellow with red spots | 0.9m | Pots and front of border |
| Cleopatra | Green, streaked bronze | Red, yellow or both | 0.9m | Pots and front of border |
For pots and small spaces, also look out for compact series such as Cannova and Tropical.
Wyoming’s bronze leaves look good long before the orange flowers open.
Growing cannas in pots
Shorter cannas make brilliant patio plants. Use a pot at least 40cm wide and about as deep. Plastic or glazed pots hold moisture better than terracotta.
Fill with John Innes No. 3 mixed with some multipurpose compost. Plant one rhizome in a 40cm pot, or three in a half-barrel. Water daily in hot weather and feed every week.
In autumn, once frost blackens the leaves, cut the stems back and move the whole pot into a frost-free shed or garage. Keep the compost barely damp over winter. Bring it back into the light and start watering in spring.
Cannas in pots need watering most days in summer. Grouping pots together helps them stay moist.
Canna pests and problems
Cannas are mostly trouble-free. Watch out for three things.
Yellow streaks along the veins point to canna virus. Bin affected plants so it doesn’t spread.
Slugs and snails chew young shoots in spring. Check plants on damp evenings and pick them off. Our guide on how to stop slugs eating dahlias works just as well for cannas.
Canna viruses cause yellow streaks, mottling and twisted leaves, and plants flower poorly. There is no cure. Dig up and bin affected plants, and don’t compost them. Buy rhizomes from a good supplier and don’t share stock from plants that look streaky.
Frost blackens the leaves in autumn. That’s your signal to lift them.
How to lift and store cannas over winter
Lift cannas after the first frost blackens the leaves, usually in October or November. In most of the UK this is the safest way to keep them.
- Cut the stems back to about 10cm.
- Lift the clump with a fork, working from well outside the stems.
- Shake off loose soil, but don’t wash the rhizomes.
- Let them dry for a few days in a frost-free shed.
- Pack them in trays or boxes of barely damp compost, leaving the stem stubs showing.
- Store somewhere cool and frost-free, such as a garage or shed.
- Check every month and remove any soft or rotting pieces.
If a rhizome looks very shrivelled, lightly dampen the compost around it. Our guide on overwintering plants covers other tender plants you can store the same way.
Frost-blackened leaves mean it’s time to lift. Ease the clump up with a fork rather than pulling the stems.
Dividing cannas
Big clumps get crowded and flower less well after a few years. In early spring, before potting up, cut the rhizome into pieces with a clean knife. Make sure each piece has at least two buds. Let the cut surfaces dry for a day, then pot up as usual.
Common canna mistakes
- Planting out too early. Frost kills the leaves, and cold, wet soil rots rhizomes. Wait until late May or early June.
- A shady spot. Cannas need full sun to flower well.
- Forgetting to feed. Hungry plants stop flowering by late summer.
- Storing them wet or cold. Wet rhizomes rot, and frost kills them. Keep them cool, frost-free and barely damp.
- Planting singly. Groups of three or five look far better.
Month-by-month canna calendar
| Month | What to do |
|---|---|
| January-February | Check stored rhizomes. Order new varieties |
| March | Divide crowded clumps. Pot up rhizomes indoors |
| April | Pot up any remaining rhizomes. Move growing plants into bigger pots if needed |
| May | Harden off. Plant out from late May in the south |
| June | Plant out further north. Start weekly high-potash feeds |
| July-August | Flowering. Water in dry spells, feed weekly, deadhead |
| September | Keep watering. Stop feeding |
| October-November | Lift after the first frost. Dry and store frost-free |
| December | Check stored rhizomes for rot |
Plants to grow with cannas
Cannas look best as part of a lush, tropical-style border. Try them with:
- Big leaves behind: hardy bananas, such as Musa basjoo. See our guide to growing hardy bananas.
- Bright flowers alongside: dahlias are the classic partner. Our guide on how to grow dahlias shares the same lift-and-store routine.
- Airy fillers: Verbena bonariensis threads between the big leaves.
For a whole garden in this style, see our jungle garden design ideas. Find more summer colour in our flowers and plants hub.
Now you know how to grow cannas, read our guide to hardy exotic plants for UK gardens for tropical-looking plants that can stay out all winter.
Frequently asked questions
When should I start canna rhizomes in the UK?
Start them indoors in March or April. Pot them up somewhere warm, such as a bright windowsill or heated greenhouse. Shoots usually appear within a few weeks. Harden the plants off and plant them out once frosts are over, usually late May in the south and early June further north.
How deep do I plant canna rhizomes?
Plant them about 5-10cm deep, lying flat with the buds facing up. Space large varieties about 60cm apart and shorter types about 40cm apart. Add plenty of garden compost, as cannas like rich soil.
Can cannas survive a UK winter outdoors?
Only in mild, sheltered gardens with well-drained soil. Frost kills the leaves, and cold, wet soil rots the rhizomes. In the mildest areas a thick, dry mulch may see them through. Elsewhere, lifting and storing them is much safer.
Why are my cannas not flowering?
Usually they need more sun, warmth or food. Cannas want full sun, shelter and rich soil. Plants in shade rarely flower well. Feed weekly with a high-potash feed from early summer, and start rhizomes indoors for a longer season.
Are cannas heavy feeders?
Yes, cannas are hungry plants. Dig in garden compost and a slow-release fertiliser at planting time. From early summer, give a weekly high-potash liquid feed such as tomato feed. Pots need feeding most of all.
What is canna virus and how do I spot it?
It’s a group of viruses that weaken and disfigure cannas. Look for pale yellow streaks, mottling or twisted leaves. There is no cure, so dig up affected plants and bin them rather than composting. Buy rhizomes from a good supplier.
How do I store cannas over winter?
Lift them once the first frost blackens the leaves. Cut the stems back to about 10cm and lift the clump with a fork. Brush off the soil and store the rhizomes in trays of barely damp compost somewhere cool and frost-free. Check them every month.
Can cannas grow in pots?
Yes, shorter varieties do especially well in pots. Use a container at least 40cm wide, filled with John Innes No. 3 mixed with some multipurpose compost. Water daily in hot weather and feed weekly.
Our team produces practical UK gardening guidance from source research, contributor records and established horticultural practice. Editorial standards are overseen by Matt W.
