Fall is the time of year to plant bulbs that will bloom in spring or early summer but it is also the time of year to dig up many bulbs that may not be able to withstand our winter soils.
When asked if certain bulbs need to be dug up before winter the reply depends on the growing situation. If bulbs are planted next to the foundation of a house then they will likely survive the majority of our southeast Missouri winters because of the added warmth coming from the foundation. In some cases micro climates are created that will also give tender bulbs an advantage to area winters by protecting a particular section of the landscape from colder north east winds for example the house or a shed or barn may protect part of the yard from wind.
In general and if 100% survival is a must, tender bulbs should be removed from the soil each year after the first frost so the risk from freezing is removed.
Elephant ears or Taro (Alocasia and Colocasia sp.) can be taken from the ground before frost and repotted as a house plant or dug up and stored as tubers for the winter. These tubers increase in size each year producing a larger plant the following summer.
Caladiums are tubers and should be dug up before a hard freeze. Cut stems back to 1 inch before storing for winter. Plant 2 inches deep in spring after danger of frost has past.
Cannas and Calla lilies are rhizomes that can be left in the ground if you live in zone 7 or higher or if you plant them near the foundation of a house where the soil will not freeze. If storing overwinter, cannas do not need to be layered but can be stored in an open box upside down. Make sure each rhizome has three eyes for regrowth in spring and water well after planting.
Dahlia is like the tuberous begonia, a swollen root or tuber. The tops should be cut back to 3or 4 inches in length after frost but before a hard freeze and carefully dug. Do not clean soil from the tuber and cure for 3 days to dry. You should clearly see an eye on each tuber which will be required for regrowth in spring. Tuberous begonia should be cured and dried for 1 week. Once cured remove any excess soil from the begonia tuber.
The gladiola is produced from a corm which is not reliable when left overwinter in the ground. Cut the stems back to 1 inch and cure for 3 weeks.
When removing below ground plant parts a soil fork is preferred to prevent damage but a shovel may also be used. Cut leaves and stems about 1 inch above the crown and remove as much soil as possible from the root area. Label what the plant is and, if known, what color. Discard anything that is damaged or rotting. Gladiolus, dahlias and calla lilies should be cured for three weeks out of direct sunlight. Allow air to dry them and then discard anything that is small and shriveled.
Bulbs, corms, tubers and rhizomes should be stored in a cool environment at a temperature between 40 and 50°F, out of any direct sun or light. An open container should be layered with shredded paper, sawdust, peat moss or sand to prevent plant material from touching and passing rot from one plant to another. Check the material several times as the winter progresses to make sure that there isn't any damage and remove anything that is rotting. To be safe wait until after all danger of frost has passed in spring before replanting tender bulbs.
If you have an email account and would like to receive a monthly publication from the University of Missouri Extension devoted to gardeners in southeast Missouri send an email to email@example.com and ask to be added to The Garden Spade Newsletter.
The Extension office is open Monday - Friday, located in Kennett, Missouri at 101 South Main Street (the old bank) on the 2nd floor. For horticulture questions contact the horticulture specialist at 573-686-8064. MU is an equal opportunity/ADA institution.
University of Missouri Extension programs are open to all.
Sarah Denkler is a horticulture specialist with University of Missouri Extension in Dunklin County.