Which Flower Bulbs Have to Be Dug Up Each Fall?

Canna Lillies

• Canna lilies are perennial flowers in tropical and subtropical areas, and grow in U.S. Department of Agriculture plant hardiness zones 9 through 12. Garden canna lilies are usually hybrids and come in hot colors of yellow, orange and red. They have big, bold leaves colored green, maroon or variegated. The sturdy plants range in height from 18 inches to 8 feet. The canna lily bulb is a rhizome, and you should use a fork or spade to dig them up when the plant foliage fades. Cutting off the tops down to 3 or 4 inches forms a handle for lifting out the bulbs. Dry the bulbs for a few hours or up to several days in a cool, dry place such as a basement. To store canna lily bulbs, arrange them on trays or hang them in mesh bags for good air circulation. To prevent fungal disease, canna lily bulbs may be sprayed with a fungicide before storage.

Gladiolas

• Most glads, including those in the Gladiolus grandiflora group, are perennial flowers only in USDA zones 9 through 11. Glads in the grandiflora group display spectacular, colorful flowers, densely packed along the stalk, and they grow 3 to 5 feet tall. All gladiolas have iris-like foliage, and their bulbs are corms. You can use a fork or spade to dig them up six to eight weeks after flowering or after freezing temperatures set in. Discard diseased bulbs, and remove soil sticking to the bulbs before drying them in a well ventilated area for at least two or three weeks. Alternatively, dry the corms in the sun for one or two days. Store bulbs so they are exposed to circulating air.

Dahlias

• Dahlias are gorgeous flowers that come in diverse sizes, colors and flower forms. Most varieties grow 1 to 3 feet tall, and flower sizes vary from a few inches to dinner-plate size. Flower forms are single and daisy-like, double or globular. Dahlias are frost sensitive and may only survive in USDA zones 8 through 11. Dahlia bulbs are called tubers and look like small sweet potatoes. After carefully digging up dahlia tubers, remove excess soil and allow them to air-dry for several hours. Store bulbs in a dry, cool place. To avoid shriveling of tubers, place them in vermiculite, peat moss or dry sand.

Calla Lilies

• Calla lilies make striking statements in red, pink, white, orange and yellow, often reaching a height of 2 feet or more. They are only perennial in USDA zones 8 through 11, so the rhizomes or tubers have to be dug up each fall in colder climates. To keep them dry during storage, place the rhizomes in a plastic bag with perlite, vermiculite, peat moss or shredded newspaper, punching holes in the bag for air circulation.