“I am hoping to overwinter my calla lilies in the cool of my basement! Will this work and any advice?” Question from Robin Van Vleet of Warner, New Hampshire
Answer: Excellent question, Robin! Calla lilies (Zantedeschia spp.) originate from southern Africa and naturally tend to bloom from late spring to midsummer, though they can be forced to bloom at other times of the year. Wintertime is their dry period, so storing them in a cool dark place through the cold months is the right idea. Here are three overwintering options, depending on how your callas are growing.
If your callas are container grown, simply place them in a cool, dark place, such as your basement, through much of the early winter months. During this time, refrain from watering them. In mid to late winter, bring them back upstairs to a full to partial sun location in your home, and begin watering them once again. They should start putting forth new foliage fairly quickly. When new foliage appears, begin to feed them every two weeks with liquid fertilizer formulated for flowers.
If your callas were growing in your garden, dig their rhizomes (roots) when fall frosts start to threaten. Place them in a container of potting mix or compost, and store them in a cool, dark place, such as your basement, through winter. If you want to plant them outdoors in spring as lush plants, pot them up in late winter and give them indoor care as specified above. After the threat of frost has passed, you can plant them outdoors. Another option is to place them in well-amended soil outdoors after the threat of frost has passed, which will result in later-flowering plants.
A third option is to maintain your callas in a cool greenhouse or conservatory through winter if you have one. If growing callas in a winter greenhouse, water them very little through the heart of the winter months.
I hope that this calla-storing information is helpful!
Black Gold Horticulturist