Container grown fruit trees - planing for winter protection
I have planted a variety of dwarf fruit trees, brambles, and muscadines in 25 gallon plastic Rubbermaid tote containers. The containers are 18 by 20 and 16 inches deep. The dwarf fruit trees are peach, nectarine, plum, sweet cherry, apple, pear. I have Arapaho and Apache Blackberries, Autumn Britten Raspberry, Boysenberry, Blueberries, and muscadines.
I'm growing these in containers because I rent the house where I currently live. I hope to buy a house or condo in a few years, so I wanted to be able to take my trees with me and either plant them if I buy a house or leave them in containers if I buy a townhome with patio.
This week I added a Jaboticaba, which is a tree from Brazil which has muscadine like fruit. The Jaboticaba is not hardy, so I plan to bring it inside during the winter as a houseplant. This got me thinking about what protection the other hardy trees would need this winter. All of the other plants are all supposed to be hardy in my location which is between zones 6 and 7. We sometimes get a few nights each winter near 0.
Since the plants are in containers, do I need to provide any extra protection since the containers might freeze this winter, while they would not if they were growing in the ground? If freezing of the root ball will kill them, I am thinking of digging a hole for each one and sinking the containers in the ground until I am ready to move in a few years. Even though it's as hot as hades here now, I was trying to plan ahead for winter, because I don't want to have to dig 25 big holes the night before a big freeze this winter.