A valuable landscape tree, the black walnut (Juglans nigra) provides shade, yellow fall color and edible nuts, among other benefits, for property owners. This deciduous tree prefers full sunlight and fast draining, fertile, moist soils in U.S. Department of Agriculture plant hardiness zones 4 through 9. The black walnut tree reaches a height of 75 to 100 feet with an equal spread. Occasionally, a black walnut requires transplanting because of an unwanted or improper planting location. Transplanting a young, immature black walnut proves more successful than moving older specimens. A suitable time to attempt the tree's move is in the fall, once its leaves drop.
Stand next to the black walnut's trunk. Measure the diameter, or width, of the trunk in inches with a tape measure, 3 to 4 feet above the ground. Multiply the measurement by 9 to determine the radius needed for the tree's root ball. For example, if the trunk's diameter equals 2 inches, then multiply 2 by 9 to get 18 inches, the distance from the trunk to the edge of the root ball.
Draw a line in the ground with the shovel's tip to mark the perimeter of the black walnut tree's root ball. Dig a circular trench around the tree with a shovel, keeping the trench 1 to 2 inches outside of the circle. Dig to a vertical depth of 10 to 18 inches, pushing the shovel's blade through any roots to sever them. Reach down into the trench and cut through large roots with loppers. Leave the tree to sit for at least six months, allowing time for feeder roots to develop within the circle.
Water the tree three to four days before digging it up. Apply 3 inches of water from a garden hose to the area surrounding the tree.
Remove weeds, rocks, plant material and debris from the new planting site. Dig a hole twice as wide as the diameter of the black walnut's root ball and 18 to 24 inches in depth. Space the hole 75 feet away from other trees, buildings and stationary objects. Pile the excavated soil next to the hole.
Tie a cloth strip to one of the black walnut's branches that faces north, marking its orientation. Spread out a piece of burlap on the ground next to the tree's root ball.
Dig up the black walnut with a shovel, digging in the root pruning trench. Dig to a depth of 18 to 24 inches to avoid damaging the tree's taproot. Push the shovel horizontally across the bottom of the root ball to cut the tree from the ground. Lift the tree out of the ground, recruiting individuals for help if needed. Place the tree in the center of the burlap.
Wrap the burlap up and around the root ball. Tie the burlap's edges around the trunk with string to hold it in place. Load the tree into a wheelbarrow, and then wheel the tree to the new planting site.
Place the tree on the ground next to the planting hole. Untie the string and remove the burlap from around the root ball. Cut off any broken, split, mushy or dead roots with a pair of pruning shears.
Set the tree's root ball in the center of the hole, spreading its roots outward. Turn the tree until the branch that holds the cloth strip faces north. Add or remove soil from the hole as needed to position the top of the root ball level with or 1 inch above ground level.
Fill the hole half full of soil, tamping it down around and between the roots. Fill the hole with water and wait for it to drain through the soil. Fill the hole's remaining space with soil, tamping it down as before. Do not bury the root ball deeper than it was previously growing.
Build up a 4-inch-high mound of soil around the outer perimeter of the buried root ball. Fill the resulting reservoir with water. Wait for the water to drain through the soil, then fill in any resulting depressions with additional soil. Do not tamp the soil down while it is wet.
Spread a 2-inch layer of mulch around the tree with a rake. Keep the mulch 4 to 6 inches away from the trunk to prevent the bark from rotting.
Water the black walnut when the top 2 to 3 inches of soil become dry. Never allow the soil to become soggy or dry out completely.
Things You Will Need
- Measuring tape
- Garden hose
- Cloth strip
- Pruning shears
- Do not fertilize the black walnut for one year after transplanting.
- Black walnut trees do not transplant well because of their long taproots, therefore, prepare yourself for the possibility of the tree's death before trying to move it.
- Do not try to lift or move large trees by yourself. If the tree cannot be easily moved by one to three people, contact a professional for help.