Q.Potted Wisteria – Winter in Connecticut
My Wisteria is a baby. It was bought in May without any leaves or vines. I potted it in a very large tree pot next to the house under the edge of a deck to give it something to cling to. It has done quite well. It also has little clumps of flowers even this late ( September 18) – The question is, will the winter most likely freeze the roots in the pot? What can I do to reduce that chance? I do not think I can lift it to bring it indoors for the winter…
A wisteria in a pot is certainly problematical. You could probably move the pot to an heated garage, for instance, with the help of a dolly and some muscle, but you would have to cut it loose from it's vines. Of course it will grow back, but it will never get beyond one year's growth. If you want to leave it, it might be okay, but I think I would want to protect the pot from extreme weather.
You should raise the pot on feet if it's resting on concrete, and make some sort of mound of material around the outside of the pot. If you've got lots of soil, you could use that; or you could build a sort of cage a few inches beyond the outside of the pot and 6" or so above the pot, and fill the whole thing with insulating material. Use the same idea as in the directions for winterizing figs in this article: https://www.gardeningknowhow.com/edible/fruits/figs/fig-cold-protection.htm
Here's some more information you might find useful: https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-winter-car.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/growing-trees-in-containers.htm
