Transplanting trees and shrubs may appear to be an easy task, but the truth is that a great many of them die if the work is done improperly or hastily. Woody plants generally are much more difficult to move than herbaceous garden plants. Exposing the roots of a tree or shrub to the air is a traumatic experience, and not all specimens survive the ordeal. But if you are about to give a facelift to a landscape design that has been neglected for years, you may have no choice but to move some of those trees and shrubs to a new location on your property. You'll have a much better chance of success if you learn the proper techniques.
Moving small trees and large shrubs can be a physically challenging task, and having assistants on hand to lift and move the plant can be very helpful. Make arrangements early to have a helper or two on hand, if necessary. Also be aware of any underground utility lines that might be present before digging. Make use of the Call Before You Dig number.
When to Transplant Trees and Shrubs
The ideal time to transplant a tree or shrub is to some degree dependent on the species, but for most trees and shrubs, late winter or early spring is the best time for transplanting; fall would be the second-best time. In summer, transplanting is not advisable because the weather is simply too hot and the stresses on the plant are too great. And in many climates, the frozen ground makes it virtually impossible to move plants in winter.
- Working Time: 2 to 8 hours, depending on the size of shrub or tree
- Total Time: a shrub or tree that is moved may require a full year to become fully established.
- Material Cost: None
What You'll Need
- Garden shovel
- Tape measure
- Garden hose
Choose a Location
Before transplanting, determine whether the tree or shrub likes sun or shade, and what its spacing and watering requirements are. Your new location should meet the needs of the plant as much as possible. For instance, do not locate a plant that craves water next to one that prefers dry conditions—their needs will be incompatible. And to be safe, make use of the Call Before You Dig number to identify the location of underground utility lines.
Calculate the Size of the Root Ball
Measure or estimate the width and depth of the root ball by doing a bit of exploratory digging around the plant. For trees, the standard rule of thumb is that the root ball will be about 11 times the diameter of the tree's trunk. The width of the new hole should be twice that of the plant's root ball. You may want to keep the depth of the new hole a bit shallower to avoid puddling and consequent rotting, especially if your soil has a lot of clay in it.
Dig the New Hole
Dig the new hole before you dig up the tree or shrub—it should be about twice as wide as the estimated root ball. It's important to move the plant into its new home and get its roots covered as soon as possible after you dig it up. The longer the roots remain exposed, the greater the chances for failure. When you reach the bottom of the new hole, resist the temptation to break up the soil at the bottom. You might think that this will help the plant's roots penetrate deeper, but it actually causes the tree or shrub to sink, inviting rot.
Begin digging about 3 feet out from the bottom of the tree or shrub, all along the perimeter. Get a feel for where the central mass of roots lies. Also, begin to estimate the weight of the plant plus the roots plus the soil clinging to roots. You may need someone (perhaps two people) to help you lift it; now is the time to plan to call for help.
The idea is to keep as much of the root-ball (roots plus soil) intact as possible. But with large plants, you may find it hard to keep the entire root ball intact, since it will be very heavy. On large, mature plants, you will usually need to cut through some roots with a sharp shovel or with pruners. Be sure to make a good, clean cut.
Transfer the Plant to a Tarp
Once you have removed enough soil from around the sides of the plant, you will be able to slip your shovel under it and begin to loosen the plant's grip on the soil below it. After it is loose, spread a tarp on the ground nearby and gently move the tree or shrub onto the tarp. With larger specimens, you may need two or even three people to help lever the root ball up out of the ground.
Move the Plant to Its New Hole
Using the tarp as a sled, drag the plant over to the new hole. Gently slide it into the hole and adjust it so it is upright. The plant should be at the same level, or slightly higher than it was in its old location. Shovel the excavated soil back into the hole. Tamp this soil down firmly and water it as you go, to eliminate air pockets. The formation of air pockets could cause the tree or shrub to shift after transplanting.
Mound up the soil in a ring around the newly transplanted tree or shrub, forming a berm that will catch water like a basin. This will help keep the transplant's roots well watered until it becomes established.
At one time, the standard advice was to blend peat moss or compost with the soil before filling in around the transplanted tree or shrub. Now, however, many experts believe that the fill soil should be identical to the surrounding soil outside the planting hole. This will encourage new roots to explore outward rather than remaining confined in a small area of unnaturally rich soil.
Care for the Plant
Spread a 3-inch layer of landscape mulch around the transplant. But keep the mulch a few inches away from the base of the tree or shrub, to promote air circulation and to discourage rodents from nibbling on the trunk. (Rodents become emboldened by the cover that the mulch provides.)
Then water, water, water. The first summer will be a difficult one for the plant unless it gets plenty of water. Frequent watering is essential to success when transplanting shrubs and trees.
Tips for Transplanting Trees and Shrubs
- Root pruning is one technique sometimes used to make transplanting large trees or shrubs. A tree's root ball is typically about 11 times the diameter of its trunk, which means that a 3-inch-diameter trunk indicates a root ball nearly 3 feet across. Such a tree will likely require that you sever the outer roots in order to lift the large root ball from the ground. Root pruning involves severing the outer roots of the tree well in advance of digging it up—some experts recommend doing this in the fall prior to spring transplanting. This can be done by cutting or trenching vertically down into the ground around the perimeter of the root ball to a depth of at least 12 inches. The goal is to sever all lateral roots extending out from the tree.
- For trees with trunks larger than about 3 inches in diameter, hire a tree service to move your tree with a motorized spade. Large trees generally die if you try to dig them up by hand.
- If a tree or shrub must remain out of the ground for more than a few hours before replanting, as may be the case if you are moving it a long distance, swaddle the root ball tightly in burlap and keep it well watered until it can be planted. Trees and shrubs can be kept alive for many weeks or sometimes even months in this fashion if the roots remain embedded in the soil.
- If transplanting during hot weather, provide shade for the plant for a week or so. This will keep the plant from wilting and prevent sun scald to the leaves.
- Trees and shrubs with thick, fleshy roots often do not react well to transplanting in the fall. These include magnolia, tulip poplar, oaks, birch, rhododendrons, hemlocks, and flowering dogwood. These species should be transplanted in the spring instead.