Weeping willows (Salix) are members of the family Salicaceae. They are deciduous trees that will grow well outdoors in USDA planting zones 5, 6, 7, and 8. Weeping willows are graceful trees, with their branches seeming to flow toward the ground. Mature trees can obtain a height of 40 feet and have a 35-foot spread. As with any tree, it is easier and best to transplant a weeping willow while it is still young. Considered a hardy tree, weeping willows should transplant well providing you meet their requirements.
Start the transplant two to three months in advance of replanting by obtaining a root ball that is 2/3 as large as the leaf spread of the weeping willow. For example, if the weeping willow has a leaf spread of 6 feet, the root ball should be 4 feet across.
Prune the weeping willow's branches back by 1/3. Trim the entire tree's canopy so the tree will put its energy into the root system after the transplant.
Cut through the feeder roots 6 inches closer to the trunk than where the final cut will be made. Slice down through the feeder roots around the entire diameter of the tree with a flat-edge shovel. Make a small trench as you make the cut. Allow the tree to adjust for several months before making the final move.
Remove weeds or grasses from the planting site. Dig a hole that is two times larger than the root ball but is no deeper than the tree is growing in the ground.
Amend the new planting site with compost, working the organic material into the soil to a depth of 1 foot. Water the soil in well before placing the tree in the planting hole.
Lay a tarp beside the weeping willow and mark the side of the tree facing the sun. Dig 6 inches out from the initial cut. Cut through any new feeder roots and underneath the tree's roots to release it from the soil. Cut any roots holding the tree in place with loppers. Retain as much of the weeping willow's root ball as possible.
Lay the weeping willow on a tarp, once it is out of the soil. Drag the tree to its new planting site, being careful not to disrupt the root system too much.
Water the root ball before placing the weeping willow in its new planting site. Place the tree in the hole with the mark facing in the same direction the tree was originally growing.
Cover the planting hole halfway with soil and firm up around the base of the plant. Continue filling the hole with soil, firming up again once you are finished.
Water the weeping willow tree well, making sure the water reaches deep enough into the soil to get to the root system. Water two to three times per week until the tree establishes itself. Continue watering the weeping willow one to two times per week, depending on weather conditions.