Whether you've just brought a spindly young Japanese maple tree (Acer palmatum) home from the nursery or are moving a large, established sugar maple (Acer saccharum) from the front yard to the backyard, transplanting is a serious undertaking that can make or break the future health of your tree. Young trees are more adaptable than established specimens and are more likely to transition easily.
When and Where
Transplant your maple tree in early spring, before tender new growth starts to emerge. Although you can transplant in fall, avoid transplanting in summer, when hot temperatures are more likely to stress the tree. Only plant where hardy: Japanese maple is hardy in U.S. Department of Agriculture plant hardiness zones 5 to 8, while sugar maple is hardy in USDA zones 3 to 8. Both trees prefer dappled sunlight or partial shade. Take the size of the tree into consideration when transplanting and space for mature growth; sugar maples can grow up to 80 feet tall and crowd power lines, houses and sidewalks.
Preparation is Prosperity
Maples require well-draining, slightly acidic soil and full sun to partial shade, depending on variety. Prepare the soil prior to transplanting by digging a hole that is three times the width of the root ball and just a little bit deeper. Digging a large hole improves the quality of the soil by introducing air and loosening it, which will make it easier for the roots to become established. Even if you're planting the tree right after digging, keep the tree in a shaded area with its roots moist and covered, so it doesn't dry out. If you're planting a bare root tree, soak the roots in water for about an hour before planting.
Hole New World
Place the maple in the planting hole so that it sits at the same depth as it was in the container or the ground. Fill about three-fourths of the hole with the soil you've just dug, without adding amendments. Water deeply to disperse air pockets, and fill the remaining quarter of the hole with soil. Mulch with about 3 inches of organic matter, keeping the mulch from touching the trunk, and water again. Do not tamp or press down on the soil, because this will compact it.
All About Aftercare
Most transplanted trees go through a period of shock and stress, known as transplant shock, in which they are more vulnerable to pests, diseases and other problems. Maple trees have thin bark, which makes them vulnerable to sunscald. Wrap the tree in late fall with a light-colored tree warp and remove it in spring, or paint the trunk up to the branches with white latex paint. Remove all grass and weeds, which compete for moisture, and provide about 1 inch of supplemental water a week throughout the growing season.