Cannas are beautiful, tall flowering plants that grow from bulbs and propagate via rhizomes. In the past, many gardens were created using primarily different-colored cannas. Cannas have been cultivated in many places for a long time. Caring for your bulbs over the winter is the key in many climate zones to growing cannas successfully.
Cannas are native to the Americas and Asia. Growing cannas was very popular from the Victorian era to the early 20th century. This popularity eventually led to them being viewed as "common" and the flower became less popular. Cannas have been cultivated, however, for more than 400 years and there are many hybrids in a wide range of colors.
Cannas grow from bulbs and are very hardy. Depending on the variety, cannas can grow from 3 to 10 feet tall and can have spreads as wide as 2 feet. Some hybrids have variegated leaves, but many also have solid green leaves. Canna flowers are asymmetrical, with three petals and a non-functional sterile stamen.
Cannas generally grow best in zones 7 through 10. In those zones, canna bulbs can be left in the ground to winter over. Initially, cannas should be planted in the spring after the risk of frost has passed. In colder zones, you may need to dig the bulbs up and replant the following spring.
Soils and Light
Cannas prefer loose, fertile soil that drains well. However, they also require that the soil be constantly moist. In drier climates, you may need to water your cannas frequently. Cannas need at least four hours of bright sun and require summer temperatures above 60 degrees Fahrenheit.
Winter Care of Bulbs
If you live in a zone colder than zone 7, dig up your canna bulbs in the fall. Dig carefully with a fork or spade. Dig several inches from the base of the plant to avoid damaging the bulb. Loosen the soil and lift the bulb out with the soil. Gently wash off the soil from the bulbs. Cure the bulbs in a room with no light for one to three days. The bulbs should dry in a 60- to 70-degree Fahrenheit room. Store the bulbs in a paper bag.