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Cannas

Truly exotic flowers and foliage

Canna
Canna in full bloom in September with a red-hot poker trying to steal the limelight

I’d always wanted to grow Cannas – they’re exotic, with big leaves and showy flowers – and after a visit to RHS Harlow Carr, I bought two in the plant centre.

They’re not named (which I found quite surprising) but have very dark purple foliage and burnt orange flowers – they can reach 6ft tall.

As they’re tender perennials, I started them into growth in the conservatory, then planted them into the big tulip tub, along with a golden elder (Sambucus nigra Aurea) for contrast.

Cannas can be grown in borders, but not in my heavy soil. Now in their third year, they’re going to be planted out after the last frost in my new tropical bed, which is raised and full of well-drained, rich soil.


potted-guide-logoPotted guide: Cannas

  •  Start the rhizomes (big fleshy roots) into growth in spring by planting in 20cm (8in) pots using multi-purpose compost, just covering them with compost, leaving any young shoots exposed.
  •  Water sparingly at first and keep at a temperature of 10-16°C (50-61°F). Gradually harden them off before planting out after the last frost.
  • Choose a container at least 30cm (1ft) wide, fill with John Innes No. 3 loam-based compost, with added controlled-release fertiliser. Plant the rhizomes 10cm (4in) deep.Give plenty of water in dry spells and apply a liquid fertiliser in midsummer.
  • Deadhead to encourage continued flowering. When a flower spike has no more buds, prune it down to the next side shoot – hopefully, another one will form.
  • Stake clumps in exposed positions.
  • You can grow them in cool conservatories in summer, in full light but shade plants from the hot sun.
Canna
I kept my Canna dry in their pots over winter and they have a massive start on last year

Overwintering:

  • Move pot-grown specimens to a frost-free place, or lift the rhizomes once the top growth begins to wither in autumn. Cut down the foliage and stems to about 15cm (6in).
  • Remove surplus soil, dry and then store in trays in barely-damp wood vermiculite or multi-purpose compost.
  • Place in a frost-free position for the winter. Little, if any, watering should be necessary.