Cannas are impressive tender perennials that offer height, dramatic foliage and showy flowers nearly all summer. Often used in bedding displays, tropical borders or large containers, they’re great value for money, giving years of colour and drama.
Cannas will only overwinter outside in a very sheltered garden in a mild area. To overwinter cannas in most parts of the country you will need somewhere frost free to store them in winter. Alternatively cover plants with a generous mulch and keep your fingers crossed.
How to grow cannas
Cannas are perfect for growing at the back or middle of a mixed or tropical border. Plant them in a rich, moisture-retentive soil in full sun or light shade. Water in dry spells and deadhead regularly to prolong flowering.
More on growing cannas:
Find out more about these dramatic perennials in our canna Grow Guide.
Where to plant cannas
How to grow cannas – where to plant cannas
Cannas do best in a rich, moisture-retentive soil in full sun or light shade. In the garden they’re perfect for the back or middle of a mixed or tropical border. Some can reach up to 2.5m in height. Even when not in flower, their impressive foliage offers the perfect foil for neighbouring flowers.
If growing cannas in containers choose a large pot as they put on substantial growth in one growing season. They’re often planted individually in pots as they will soon swamp smaller plants.
Follow Monty Don’s video guide on using cannas in borders:
Planting cannas in pots? Here’s how to make the most dramatic display:
How to plant cannas
How to grow cannas – planting a canna rhizome
Cannas have strong underground stems, known as rhizomes. In the dormant season you’ll find rhizomes for sale in bags in the garden centre or nursery. In the growing season they’re sold as plants.
When planting rhizomes pot them into a large plastic pot just below the compost surface. Any shoots should be just above the surface. Place the pots in a heated greenhouse, water and wait for signs of life. Once you see new shoots or roots, and all risk of frost has passed, harden them off and plant in the garden. Cannas will flower in their first year.
Cannas bought as plants can be planted directly into the garden. Water in well and feed with a slow-release fertiliser. They rarely require support.
Overwintered cannas? Find out how to start them into growth in spring, in Monty’s video guide:
How to care for cannas
How to grow cannas – how to care for cannas
Cannas rarely need staking. Water during dry spells and deadhead to keep plants flowering for as long as possible. Tropical plants, cannas are not winter hardy although they can survive mild winters. Once the foliage starts to break down in autumn, fold this over the crown of the plant and then cover with a thick layer of straw. Alternatively, dig your canna up and overwinter in a cool, frost-free place, and plant out the following year.
Here, Monty Don explains how to overwinter tender cannas, along with dahlias and cosmos:
Watch Keith Hayward of Hart Cannas explain how to care for cannas, including when to water them and how to overwinter them:
How to propagate cannas
How to grow cannas – canna rhizome
Divide cannas in spring before planting them back outside in the garden, or dig them up if you have overwintered them outside (wait for all risk of frost to pass, first). Remove sections of rhizomes with at least two or three growing points and pot on.
You can grow cannas from seed but they won’t come true to type.
Growing cannas: problem solving
Canna virus with affected foliage
Cannas are trouble free if grown in the right conditions. The biggest problem you will encounter is plants that are too happy – in a few years plants can fill a dustbin-sized pot. You’ll need to have some strength to move the plants undercover or dig them out of the borders.
In recent years cannas have been affected by canna virus. It’s thought that this is more prevalent on plants that are bought as rhizomes. Try to buy plants from virus-free suppliers.
Canna varieties to try
Canna ‘Queen Charlotte’
Canna ‘Wyoming’ – favoured for its bronze foliage. Bright orange flowers from July to September. Reaching a height of 2m when grown in a fertile soil
Canna ‘Queen Charlotte’ – spectacular bright red flowers with bright yellow edges. Flowers in July through to October. Reaches a height of 1.5m
Canna ‘Durban’ – burgundy striped foliage with bright orange flowers. Reaches about 1.5m
Canna ‘General Eisenhower’ – very dark maroon/bronze foliage with orange flowers that have a slight mottling of red. Reaches 2m
Canna ‘Panache’ – a very different looking canna with finer flowers and narrow foliage. Pale pink flowers that you might not assume belong to a canna. Reaches a height of 2m