To make it possible to safely dig small trees or shrubs in the woods, such trees should be root-pruned a year or so before they are moved. In the spring, sever half the roots by forcing a sharp spade into the soil around the plant alternately leaving a shovel width of untouched soil between cuts. The circle of cuts should be slightly smaller than the size of the ball that will eventually be dug. In the fall, sever the other half of the roots, thus cutting all the roots that are at a depth of a foot or less. The tree can then be moved the following spring.
Recent research indicates that most of the new roots grow from the cut end.
Therefore, a root ball 4 to 6 inches larger than the root-pruned area must be dug to get the newly developed roots. Root pruning is also used to force a vigorously growing fruit tree, wisteria vine, or dogwood into bloom. Using a spade to cut the roots early in the spring, as explained above, is all that is sometimes necessary to force a tree, shrub, or vine into bloom the following year. This site was developed for the Arizona Cooperative Extension , College of Agriculture , The University of Arizona . The University of Arizona.