Ken - Hello over there! I have the EXACT same problem at my house. According to Greg Stack, one of our horticulture educators, "the suggested rule of thumb for size of root ball based on the size of the trunk diameter is for every inch of trunk diameter you need about 10 inches of root ball. When digging make sure the soil is moist, use a sharp diggin spade and try to dig a root ball that stays together. You need to dig the plant so you can undercut the ball of soil to a depth of 18 inches or so, again dependant on the size. After doing this try to lift the ball and place it on large peices of burlap or similar material to enclose the root ball and tie it up for transport. When moving try not to break the ball and get it to where it is going in one piece. Hope that helps!
