Looking for a touch of the tropics in your home garden? Plant a canna lily – its lush foliage and exotic flowers make it the perfect choice for adding tropical appeal. Over the past few years, a trend toward creating gardens with a distinctly tropical look has been gaining momentum. Trends come and go, but this one looks like it’s going to stick. In fact, it’s bordering on becoming a movement! The canna lily is a great place to start, as it can add a bold and exotic presence to any landscape, and its cultivation could not be simpler.
Once seen only in public gardens or in the yard of the most fanatical gardener, the canna lily is going mainstream. The Royal Horticultural Society recognizes nearly 125 cultivars ranging in size from dwarf types growing to 45 centimetres, to larger types growing to two metres. Flowers are large, nearly seven to 10 centimetres across, and are held on spikes well above their foliage. Colours are usually in the warm tones of yellow, peach, orange or red, with many bicolours available. Their bold and luxurious foliage ranges from solid green to variegated to black. Cannas are versatile plants, and can be grown directly in a garden bed or in a container, while many can even be grown with their roots immersed in water (provided it is warm enough – about 15°C is ideal).
The 25 to 50 species of wild canna lily are found in tropical and subtropical forests of the New World (some botanists add species from Asia to this genus). Most of the canna cultivars that we grow in our gardens are complex hybrids. Close relatives of banana and ginger, they are not hardy in most of B.C. Cannas range in hardiness from zones 8 through 10. The rhizomes may overwinter in the milder, drier areas of the province, such as Victoria, the Gulf Islands, or White Rock, but for most areas they must be planted seasonally. Rhizomes (thickened underground stems) are available at most retail outlets in early spring and can be treated in two ways: potted immediately and grown indoors (transplanting once the risk of frost has passed), or planted directly into the garden after last frost. Potting rhizomes up in early spring is a great way to get a head start. Many retailers offer pot-grown plants that provide instantaneous effect, but at an added expense. For the more adventurous gardener, there are cultivars that can be grown from seed. You will need to get seeds started early, as it takes about 90 to 120 days from germination until flowering.
A word of warning – some of the more exotic cultivars can be pricey. When purchasing a canna, consider it a long-term investment. Each fall the plants can be dug, the rhizomes harvested and then stored for use the following season. Cannas should be dug before first frost. Cut off all top growth to within 15 centimetres of the rhizomes, wash off all soil and remove any excess feeder roots to within a centimetre or two of the rhizome. Allow the rhizomes to dry for a few days and then pack into trays or boxes, covering them with loose peat moss. Store in a cool location until the following spring – a heated garage, basement or storage locker is ideal. Keep the peat moss lightly moist and avoid exposure to freezing or warm temperatures (less than 8° to 15°C is preferable).
Rhizomes should be potted in March. If using stored rhizomes, remove the previous year’s dried stems. Cut each rhizome into smaller chunks, each 10 to 15 centimetres. Ensure that each chunk has a few buds and that the flesh is firm and white. Place one or two pieces of root for each one- or two-gallon pot. The rhizomes should be planted into a light potting mix to a depth of 10 to 15 centimetres. Use the same planting depth when planting directly into the garden. You can resist dividing the rhizomes and pot these clumps into larger pots to get a bigger show, but it is always nice to increase the number of plants from year to year, giving away any extras to friends.
Few plants could be easier to grow. Cannas require ample heat and light for optimal growth, doing best in full sun. In nature, they are found growing in open boggy locations, but in cultivation will tolerate drier growing conditions. They can be slow to get going on the coast, but once their roots have settled in and air temperatures start to warm, growth is phenomenal. From one rhizome, an immense plant can develop (depending on the cultivar). Given ample sun, water, organic-rich soil and fertilizer (a one-time application of a controlled-release fertilizer such as 14-14-14, or biweekly applications of soluble fertilizer 20-20-20 are excellent), canna lilies will spoil you with unprecedented growth, flowering freely from early summer until frost. They are sturdy plants that require little attention once in the ground – almost no staking or deadheading is required, and they are subject to few pests or diseases.
There is no denying the stately beauty of a canna lily – a beauty that is even further enhanced when paired with other bold foliage and flowers. Cannas have a tendency to look out of place if thrown into the middle of a perennial border or grown singularly in a display. They are best used as a centrepiece or as a foil to other plants, and look exceptional when planted en masse.
A word of warning, however: Tropical-style gardening comes with some hidden costs and headaches. Using unusual plant material can equal added expense and effort. Many of the plants that make the best companions for cannas can be expensive and are not always hardy. Extra work is involved in keeping these plants alive from season to season. But you don’t have to go all out to add a touch of the tropics to your garden. Start with a container filled with a few choice plants and see how it goes. Just make sure a canna is the centre of attention!
Sources: Many of the cannas recommended here can be found at your local nursery, or ordered through these sources: Hawaiian Botanicals Local B.C. grower offering a good selection of potted canna cultivars. (604-270-7712; www.hawaiianbotanicals.com) Stokes Seeds Offers some canna seed. (1-800-396-9238; www.stokeseeds.com) Veseys Mail-order/online bulb company offering a good selection of canna rhizomes and seeds. (1-800-363-7333; www.veseys.com)
Bruce McDonald is chief propagator and an educational instructor at VanDusen Botanical Garden.