Come late summer, canna lilies are in their full glory. These warm-weather-loving bulbs grow slowly at first in the cool conditions of early summer, but put on growth daily with the increasing heat and culminate in a tall, flowering plant with large leaves that are the size and shape of banana plant leaves. Many newer varieties have striped leaves with mixed colors, making this an attractive plant even when not in flower.
In most areas canna lilies are grown as an annual or the bulbs or tubers are dug and stored in winter like those of dahlias. Cannas can be left in the ground if temperatures don’t go below 5 degrees F in winter in your area. Mulch the ground well to help them survive.
Plant in spring in containers or in well-drained soil amended with compost in the garden. Wait until the soil has warmed to plant. Canna lily bulbs can rot if exposed to cool, damp soils. Since the plants can grow up to 7 feet tall and have such large leaves, fertilize every few weeks with an organic plant food to keep them growing strong, especially when growing in containers. Also, keep the plants well watered.
Protect canna lily leaves from Japanese beetles by handpicking, trapping, and spraying the beetles with Neem oil. In most areas other than the far North, canna lilies will flower toward the middle to end of summer. They make great back-of-the-border plants or look majestic planted in large containers with cascading annuals such as calibrachoa and scaevola. Before a hard freeze, cut back the plants to the ground, dig up the tubers, let them dry in a warm, well-ventilated garage or barn for a few days, and store in a cool basement in slightly moist peat moss. Some good varieties to try include ‘Tropicanna’ with orange flowers and purple, yellow, and red striped leaves; ‘Black’ canna with bold red flowers and dark purple leaves; and ‘Sunburst’ with pink flowers and yellow and green striped leaves on a dwarf, 3-foot-tall plant.