I'm homesteading and have several fruit trees planted in large kitty litter buckets the trees are about 1 to 2 years old best way to protect them over the winter. The fruit trees I plan to transplant to a larger buckets (3ft by 3ft by 3ft)and make espaliers out of them. The type of trees you see in Europe were predominantly branches shoot laterally from a main tree usually anchored against buildings. In addition I also have several Berry plants I was concerned about losing also planted in kitty litter containers. Most of the berries are local Missouri. Thank you for your time and consideration in this matter.
Winter Protection for Fruit Trees
Certified GKH Gardening Expert
I would, first, recommend making sure the container is an acceptable plastic type, such as HDPE (High Density PolyEthylene), for planting in. Some plastic types can interact with soil nutrients and produce unwanted chemicals that you plant will attempt to use as nutrients. Most food grade buckets are good. Pickle buckets make excellent containers if they are thoroughly cleaned of teh vinegar. Paint the outside, or tape the outside with some color. Lighter colors are better to disperse heat, and darker colors can retain heat. So if you can make some sort of shell that is removable, then you can adjust the color for the time of year.
As for cold hardiness, This depends on the tree. Apples tend to be much more hardy than peaches, and pears can tolerate a wide range of conditions. Most fruit tree need no protection in your area. If you feel that you need extra protection, then you can wrap blankets around the pots during the coldest parts of the year.
For espalier pruning- You will want start doing this as soon as possible. You can prune when it is dormant with no problem. Young trees can be shaped a lot easier than a mature tree. I will include an article for help with that.