How do you prepare summer bulbs such as calla lilies for the winter?
Zantedeschias or calla lilies are tender perennials grown from tubers and like other summer bulbs, they should be dug from the garden and stored when planted in cold winter climates. Callas are marginally cold hardy in my zone 7 garden so I choose between two methods; sometimes I plant them in pots and store in my lathe house over the winter or I treat them as an annual and let nature take its course.
Here is a list of summer bulbs, including calla lilies that require winter protection with details on how to store them.
Begonias
Hardy in zones 9 to 11. In fall, once the flowering ceases and before the first frost, bring in begonias for the winter. Leave them alone until the stems dry and pull off easily. Store “as is” in pots or dig up the tubers. Dug tubers should be allowed to dry for a few days and then stored in layers of slightly moist vermiculite or sawdust. Keep in a room that stays at approximately 40 F to 55 degrees F.
Alocasia
Hardy in zones 9 to 10. Treat as an annual or dig and store the bulbs for winter. If growing in a flower bed, dig the bulbs after a frost has killed the foliage and store them in saw dust or mulch. If grown in containers, move the container indoors and allow the plant to go dormant.
Caladium
Hardy in zones 10 to 11. Treat as an annual or lift them after the first frost. Allow the tubers to dry thoroughly, and then layer the tubers in dry peat or vermiculite and store them in an area that remains around 50 to 60 degrees F. Check the tubers occasionally to make sure they are plump but dry.
Calla Lily
Hardy in zones 7 to 10. In northern gardens, after the foliage has been damaged by a frost, cut off the tops about 2 inches above the soil line. Dry the calla rhizomes in a warm, dry location for one or two weeks. Then bury the rhizomes in vermiculite, sawdust, or peat moss, and store them in a cool (45 to 55 degrees F), frost-free area. Callas can be started indoors ahead of time in late winter to early spring, and then moved to the garden after the threat of frost has passed. Callas grown in pots can be brought indoors before the first fall frost to continue growing over winter as houseplants. Move them outdoors again in spring, once frosts are passed and night temperatures remain above 40 degrees F.
Canna
Hardy in zones 7 to10. After first fall frost has blackened the foliage, or the foliage begins to wither, cut the stems back 4 to 6 inches. Store cannas grown in containers as is, with no further watering. In ground rhizomes should be dug and stored. Allow the fleshy stem stubs to dry before them packing the tubers in slightly moistened sand, vermiculite or peat moss. Keep in a cool location (40 degrees to 50 degrees F). Check on them periodically to make sure they do not dry out.
Colocasia
Hardy in zones 8 to 11. Treat as an annual or bring them indoors to overwinter. Dig the bulbs after the plant has died back and store them in sawdust or mulch. If grown in containers, move the container indoors and allow the plant to go dormant.
Crocosmia
Hardy in zones 6 to 10. The variety ‘Lucifer’ is cold hardy up to zone 5 if given a protective layer of mulch. In colder zones, before the first fall frost, dig the corms and store them on a tray in dry peat moss in an area with temperatures between 40 degrees F to 48 degrees F.
Dahlia
Hardy in zones 8 to10 and often in zone 7 with a heavy layer of mulch. Store potted dahlias in their containers. In ground bulbs should be lifted. Be careful not to break or cut the tuber “necks.” Do not wash the bulbs to remove soil. Store them away from drafts at 40 degrees F to 50 degrees F in a paper bag or box filled with peat moss or dry sand. Check them frequently for shriveling or decay.
Eucomis
Hardy in zones 7 to 10. These bulbs are best grown in containers that can be brought indoors for winter protection. Cease watering and leave bulbs undisturbed.
Gladiolus
Hardy in zones 7 to 10. Dig after the foliage browns. Cut the stems back to 1-inch above the corm. Dry, and then remove the excess debris and store them in paper bags. Keep the bags in an area safe from mice at a temperature between 35 degrees F to 45 degrees F. If gladiolus were grown in pots, bring them indoors, stop watering and store them in their containers until spring.
Oxalis
Hardy in zones 8 to 10. This plant can be treated as a houseplant indoors or it dig up from the garden and dry it with the soil attached. Plants grown in containers can be dried and stored “as is.”
Tuberose
Hardy in zones 8 to 10. Dig up before the first hard frost. Cut the foliage back to 2-inches and store it in peat moss at 60 to 65 degrees F. Check frequently for shriveling.