The black walnut (Juglans nigra) is grown as a valuable timber tree, for nut production, as a food source for animals and as a landscape specimen. The tree grows rapidly to a height of 70 feet with a 70-foot spread. It tolerates a wide range of soils and conditions. Young trees and seedlings have a very long tap root, which can make transplanting the black walnut difficult. Planning for a successful transplant of a tree must take place a year prior to the actual transplant.
Cut the tap root of the black walnut tree a year prior to transplant. Thrust a shovel deeply under the tree to sever the tap root 8 to 10 inches under the tree. Severing the tap root causes the tree to grow additional roots outward to make up for the loss of the transplant. The lateral roots produced are easier to dig up during transplant.
Choose a location that offers full sun to partial shade to plant the black walnut transplant. The soil should be well-draining with no standing water. Transplant the black walnut in the early spring.
Dig the transplant hole twice as large as the tree's root system. Mix organic material such as peat moss or leaf debris into the soil at a ratio of 50 percent organic material with 50 percent garden soil.
Dig around the black walnut tree carefully. Dig at least 2 feet out from the trunk if the tree is under 3 years old. If the tree is older than 3 years old, dig at least 36 inches out from the trunk. Work the shovel down and under the tree, lifting upwards. Once the tree is loose, gently lift it from its hole.
Place the tree into its new transplant hole. Firm the soil and organic matter around the trees root system. Make sure no air pockets remain between the soil and the roots. Plant the tree at the same depth it was planted at in its previous location.
Water the tree thoroughly. Apply 3 to 4 inches of mulch such as peat moss or bark chips around the transplanted tree to help the soil retain water and keep weed growth at bay.