What Is the Eye on a Canna Bulb?

Eyes

• Technically, canna lilies do not grow from "true bulbs," but from rhizomes, which are similar to true bulbs in that they are storage structures for plants. However, rhizomes grow horizontally, near the soil's surface instead of straight down, as true bulbs do. The "eye" on a canna rhizome is a nodule -- a small bump -- of plant cell activity from which new plant growth develops, according to the Cornell Cooperative Extension of Oneida County. Plant rhizome sections with eyes in spring for new plants to grow.

Digging Out

• As tropical plants, in the colder U.S. Department of Agriculture plant hardiness zones 6 and below, canna lily rhizomes must be dug out of the ground each fall, according to the Cornell Cooperative Extension of Oneida County. After frost kills canna foliage, carefully dig into the soil around plants and lift up the rhizomes, gently removing any soil that comes off easily. Cut stems and foliage back to 2 to 3 inches and gently hose off any remaining soil on rhizomes, advises University of Minnesota Extension. Rhizomes can then be divided.

Dividing

• Divide rhizomes into sections with three to five eyes per section; most rhizomes have natural breaking points. Place sections into plastic bags with air holes. Because dried-out rhizomes cannot produce new plants, the Cornell Cooperative Extension of Oneida County suggests adding peat moss to the bags to help maintain moisture balance. Store rhizomes in a cool, dark place, between 45 and 60 degrees Fahrenheit, such as in a refrigerator or garage, until spring. In U.S. Department of Agriculture plant hardiness zones 7 through 10, canna rhizomes can be left in the ground during winter, dug up in spring every two to three years and divided, according to the extension. Just allow the rhizomes to dry for a few days before planting.

Planting

• After danger of frost passes in spring, plant rhizomes in the ground horizontally, with eyes facing upward, 3 to 4 inches deep and 1 1/2 to 3 feet apart, in a location receiving full sun and in soil high in organic matter. Provide fertilizer when rhizomes are planted and then on a monthly basis throughout summer, recommends Washington State University Whatcom County Extension, and water regularly, providing at least one deep soaking each week, keeping soil moist, not soggy. Deadhead canna lilies for best blooming.