How to store canna bulbs: easy tips for overwintering these plants
Learning how to store canna bulbs can be useful if you have these perennials in your garden and you're expecting colder temperatures on the horizon.
Cannas, otherwise known as canna lilies, are a bold addition to any outdoor space with their showy, hot-hued, summertime blooms. Their exotic appearance makes them ideal for tropical-style planting schemes, and they do well in both borders and containers.
But, as cannas are tender, they won't survive frosty conditions without your help, particularly if your garden's soil is heavy. So, as part of your fall gardening checklist, it's wise to provide some protection, so you can enjoy these plants again next year.
How to store canna bulbs in 5 simple steps
Learning how to store canna bulbs is straightforward, and well worth doing if you want the best chance of enjoying new blooms in your flower beds each year.
Wait until fall, when the plant has finished flowering and the foliage has withered. Then, cut it back using a pair of pruning shears, also known as secateurs, to about 6in (15cm).
Carefully lift the canna rhizomes using a garden spade. Avoid using a garden fork which can damage them.
Brush away excess soil from the bulbs. Then, place them in trays filled with barely-damp wood vermiculite or multi-purpose compost, suggests the RHS. Position the trays somewhere cool, dry, and frost-free: a garden shed, greenhouse, or garage, for instance.
'Try not to let the rhizomes dry out,' says John Negus of Amateur Gardening. However, don't allow them to become too damp, either. Check on them periodically and water sparingly if needed. At the same time, keep an eye out for any which are showing signs of rot, and discard them.
In spring, you can pot up the rhizomes in compost, water lightly, and keep them somewhere warm (50-60˚F/10-16˚C). Harden them off before planting outdoors, once the risk of frosts has passed.
John Negus
Gardening Expert
John has been a garden journalist for over 50 years, has written four books, and has also delivered many talks on horticulture. As well as this, he regularly answers readers' questions in Amateur Gardening magazine, including many on canna lily care.
Cannas make excellent container plants, and if you have grown yours this way, you don't have to lift them for winter. Instead, simply move the pots somewhere that's frost-free.
Is it always necessary to lift canna bulbs for winter?
Like dahlias, canna rhizomes can survive outdoors if you have mild winters and free-draining soil, but it's wise to mulch them. 'Remove the leaves of your canna as they die away and cover the crowns with 6-8in (15-20cm) of well-rotted manure or compost as insulation,' says John.
'Like many borderline-hardy plants, they get more hardy the better established they are,' he adds. Lifting them, however, is a safer bet for success – particularly if your garden is hit by an unexpected frost during the colder season.
Can you divide canna bulbs?
Many perennials can be divided – it's easy and a great way to get free plants for your garden.
With cannas, 'it is normally recommended that division takes place either on lifting the rhizomes in autumn, or on starting them into growth in spring for plants that were lifted,' says John.
If you're planning on mulching your canna bulbs for winter rather than storing them, lift and split them once flowering has finished and growth has ceased, but before the foliage has died away. 'They should be all right to be replanted,' John says – just remember to mulch them before temperatures drop.
