Answer: It is very difficult to overwinter plants in containers outdoors, especially on a deck where they are elevated and exposed to cold air from below in addition to the sides. The reason is the roots are not insulated the way they would be when planted in the ground. This means they are exposed not only to extreme cold but also to the freeze thaw cycles due to oscillating temperatures. Both are very stressful on plants. So although this plant would be winter hardy when planted in the ground, it may not survive when planted in a container. Wisteria is also a very large aggressive vine that would soon outgrow even a large container. If you truly want to use wisteria, you could plant it in the ground below the deck and allow it to grow up to it. If you want to screen the deck quickly, you might try a quick growing annual vine planted in a large container -- such as a half barrel size. Morning glories or the moonflower vine for example are fast growers. I hope this helps.
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