Cannas emerge from dormancy and hit the horticultural market in late winter and spring, so now is the time to get the show started. Numerous varieties are available from on line and local nurseries, either as potted plants or as bare-root rhizomes (the technical name for the thickened underground stems that give rise to all that splendiferous summer growth).
Newly purchased plants should be grown indoors in a suitable potting mix until danger of frost has passed, such as Fafard Professional Potting Mix. Ten- to twelve-inch plastic pots and a two-inch planting depth work well for this initial, indoor growth phase. For their outdoor, summer home, cannas need containers of a grander and more massive order planted in a water-holding mix, such as Fafard Ultra Outdoor Planting Mix. An 18-inch-plus clay or ceramic pot (or something in the way of a cast iron urn) is ideal. Large wooden or terra cotta planters also work well. Simply knock the plants out of their temporary, indoor containers and place them at the same depth in their outdoor quarters. Then stand back and watch the fireworks happen (making sure to water liberally and fertilize regularly through summer).
Although spectacular on their own, containerized cannas make an even more extravagant statement if combined with other heat-loving plants. For example, the flowers and foliage of gold- and red-hued Coleus provide a striking foil for the sunset foliar tones of Canna ‘Phaison’ (right). The possibilities are practically limitless, given cannas’ wide range of floral and foliage colors.
When choosing cannas for container gardening, the sky’s the limit. For a lavish summer display on a less colossal scale, use a “dwarf” canna cultivar such as ‘Pink Sunset’, which offers dazzlingly variegated leaves and soft pink flowers on 3-foot (rather than the usual 5- to 10-foot) plants.
Or you can go the other direction and opt for something outrageously gargantuan such as the banana canna, ‘Musaefolia’, a Victorian-age behemoth that towers to 14 feet. A bathtub of a container (and lots of water) is recommended.
Cannas slow their pace in fall, requiring reduced water as they gradually die back to their rhizomes. Dormant plants can be moved indoors, pot and all, for the winter, or the rhizomes can be lifted and stored in paper bags in a well-ventilated location. Either way, cool temperatures (below 60 degrees F) are best for storage.
In early spring, move containerized cannas to a warmer niche and water sparingly until growth resumes. Split overwintered bare-root rhizomes into divisions of 3 or more “eyes” (the red, swollen growth points spaced along the rhizomes), and plant them in containers (as described above). And start planning this year’s summer spectacular.
