Deciduous trees such as Dogwood are best moved when they are dormant. The best time is in the Fall so that the tree has less stress on it. You can move it in the Spring as long as you make sure not to break up the root ball in any way and give it plenty of water to prevent transplant shock. Dig a hole larger than the root ball and plant slightly above the soil line. Use mulch around the tree but not touching the trunk. Keep well watered throughout the growing season.