Mid-Atlantic Gardening: OverWintering Tropicals - A Mid Atlantic Survey, 2 by coleup

coleup wrote:
Reserved for info on overwintering Elephant ears. I will concentrate of the varieties I have shared at our swaps. But first some general info.





How to Over Winter Colocasias

I have excerpted passages from an article on the Plant Delights Nursery site Tony Avent is one of the pioneers in tropical introductions that have made them a favorite garden addition for so many in recent years. Indeed, some of the offspring I have shared may be traceable back to Tony, so I'll use him as a 'general rule of thumb' guide from which we can vary and supplement with our own experience. The complete article is available here :http://www.plantdelights.com/Colocasia-Elephant-Ear-Perennial-Plants/products/503/

I am numbering the paragraphs so that we can refer to them in our comments and discussion. Any helpful comments I make will be in italics and designated with an asteric *

"How to Overwinter Colocasia bulbs

1-As the day length shortens, Colocasia switch their energy resources from producing leaves to flower and corm production. The production of leaves will become smaller and the corm will swell noticeably. At this time, most of the current season's roots will die off. It is important to understand this physiological change in order to successfully overwinter your elephant ear. *This timing will vary for each of us each season. But, never fear as a frost will not kill the corms but will turn some leaves to mush!

2-There is also quite a difference in winter hardiness of Colocasia. Colocasia gigantea Thailand Giant Strain is a solid USDA Hardiness Zone 8b, while Colocasia 'Pink China' is reportedly winter hardy to Zone 6. The rest fall somewhere in between. Typically, triploid cultivars are about a half zone hardier than their diploid counterparts. From Zone 8b south, most Colocasia should be reliably winter hardy in the ground without protection. This successful zone of cultivation also extends into Zone 8a, but some marginally hardy cultivars may be slow to return after a hard winter.

3-In Zone 7b, most Colocasia will return without benefit of mulch with a few exceptions. In this hardiness zone, hardy Colocasia may survive, but the large central corm can freeze and rot during the winter, leaving only the smaller offsets to survive. In this case, returning plants may not reach full size during the ensuing season. To overcome this, cover the clump after the first frost with a 1' tall pile of shredded leaves, which works well to protect the main corm. The plants will grow through the leaves when they re-emerge in spring. * I'm in 7b but I'd rather not chance it, so I bring mine in every year. Remember, too that drainage must be excellent in the cold ground or rot is a real possibility with these.

4-In colder zones, the same principle can be used but with a slightly altered technique. Assuming the plant has made good growth during the summer, after the first frost, encircle the base of the plant with a 3' diameter cage of hog wire and fill it with shredded leaves. If left unshredded, the leaves will pack together and hold unwanted moisture against the plant, causing it to rot. When new leaves emerge in spring, remove the cage and filler.

* Ok , here we go!
5-Northern gardeners (Zone 7a and north) will need to bring their elephant ears indoors before the temperatures drop below freezing. Over winter, elephant ears can be grown indoors as potted house plants * This means supplying the warmth and humidity to keep them happy and some will need more light than others Let's call this "Houseplant Method." If you grow your elephant ears outdoors in containers during the summer, cut back all but the top two leaves, then bring the pot indoors before the first frost. If growing elephant ears in the ground during the summer, pot them before frost in an appropriately-sized container and bring them indoors. *Cut back on water and feeding as you would any house plant. Treat for pests etc as necessary. ( More on this under Pests and Diseases if we ever get to that section lol J)
6-Alternatively, the pot can be placed in a cool area (45-60F is ideal) where the plant will not freeze . If there is bright light and ideal temps the plants will grow very slowly and achieve semi-dormancy . * Let's call this "Semi-Dormant Method"Do not over water in winter as the plants are still semi-dormant. * Cooler temps and less light = more dormancy = longer time to wake up and resume active growth but generally quicker than the"Full Dormancy Method"which is similar to how cannas are stored for the winter, bareroot in peat moss, etc.or left in containers or pots and placed in a garage/basement/crawl space where they will remain cool but not freeze. No light required but moisture and drying out must be checked and managed so corms do not dry out or rot.

7-Most of the dwarf non-corm forming species should be kept growing during the winter, along with non-tuber forming selections of Colocasia esculenta including Colocasia esculenta ‘Black Magic’ and Colocasia esculenta ‘Nancy’s Revenge’. Colocasia gigantea Thailand Giant Strain is also slow to develop a large corm, so is best kept in active growth. *"House Plant Method" or "Semi-Dormant Method"

8-Varieties of Colocasia that form large corms, such as most Colocasia esculenta cultivars, can be dug up and the corms stored in peat moss for the winter. They need to be kept in a dry, cool, but above-freezing location. Do not store in an airtight container which may allow moisture to build, causing the tuber to rot. * This is our "Full Dormancy Method"

9-Don't forget to label your tubers!"



This message was edited Nov 10, 2012 8:03 PM