Dogwoods are a species of tree that do not transplant well. Dogwoods transplanted from the wild frequently have asymmetrical roots and branch growth. Even dogwoods grown in landscapes from seed often do not survive transplant. To move a dogwood tree, you must root prune the tree a year before you attempt to move it in order to contain the roots and help the tree develop new feeder roots that will help the tree survive.
Time root pruning for 1 year in advance of the dogwood tree's transplant. The best time to root prune a dogwood is in spring just before new growth begins.
Measure the trunk of the dogwood at chest height with a pair of calipers.
Calculate the diameter of the root system the tree needs to survive by adding 5 inches of root ball per 1 inch of tree trunk diameter. For example, root prune in a 10-inch circle around a dogwood with a 2-inch trunk; root prune in a 15-inch circle around a dogwood with a 3-inch trunk.
Thrust a digging spade into the ground to a depth of 10 inches. Use the spade to make a circle around the roots of the tree in the diameter you calculated.
Wait 1 year after this procedure before transplanting the tree.
Choose a new location for your dogwood that is partially shady and has well-drained soil.
Break up the soil over a wide area of the dogwood's new home with a rototiller. Spread organic soil amendments such as compost and peat moss over the soil. Do not amend just the planting hole to avoid a potted plant effect in the tree's root development.
Dig a hole in the new location for your tree that is wider than the root-pruning ring you made last year. Do not dig the hole any deeper than you expect the tree's root ball to be. The tree should be planted at the same level in the soil that it rests currently.
Insert a shovel into the ground in a ring that is 2 inches wider than your root pruning ring. Slip the shovel underneath the root ball and tilt the shovel back to lift the tree's root ball from the ground.
Place the tree into the new planting hole and fill in the sides around the tree with soil. Water so that the tree remains as damp as a wrung-out sponge. Pull grass up from the soil if it begins to grow there. Do not mulch around the tree.