Plant Guide: Canna

Cannas are exotic-looking plants with large, brightly coloured flowers held on tall stems that can reach up to 1.2 m high, rising above bold, paddle-shaped leaves. The impressive flower spikes appear in shades of yellow, orange and red, with some cultivars showing bi-coloured, spotted or striped flowers, or contrasting markings. The foliage itself is highly ornamental, ranging from fresh green to bronze or purple, and sometimes attractively variegated with yellow or pink veins.

Cannas are not frost-hardy and require protection from low temperatures. Although Canna indica is the best-known species, most plants grown in gardens are hybrids, usually sold as Canna × hybrida. A wide range of cultivars is available.

How to plant

Cannas prefer a bright, sheltered position in full sun. Plant rhizomes in late spring, once all risk of frost has passed, about 7.5 cm deep in fertile, free-draining soil enriched with organic matter. For earlier and stronger growth, rhizomes can be started in pots in a frost-free greenhouse in April and planted outside in early summer. Cannas are suitable for borders, summer bedding and large containers.

Flowering period

Flowering takes place from mid- to late summer and continues until the first frost. Once flower buds appear, apply liquid fertiliser regularly. Keep the soil evenly moist during the growing season, but avoid waterlogging. Cannas are not suitable for cutting and are best enjoyed in the garden.

After flowering

Before the first frost in early autumn, lift the rhizomes and allow them to dry. Store them over winter in slightly moist peat or sand in a cool, frost-free place. If stored too dry, the rhizomes may shrivel.

Tip

Always grow cannas in rich, well-drained soil and keep them well watered during the growing season. Protect the rhizomes from frost, as cold and wet conditions can easily damage them and reduce flowering the following year.