University of Vermont Extension 
Department of Plant and Soil Science

Spring News Article


TRANSPLANTING TREES AND SHRUBS
 
Dr. Leonard Perry, Extension Professor
University of Vermont
 
           
If you need to move a tree or shrub in the landscape, early spring before buds begin to swell is an ideal time.  If you are planning to transplant trees from the wild, you should know that this is more difficult to have plants survive successfully.
           
Even though woody plants from the wild are less expensive than nursery-grown plants, they usually are less vigorous, with roots and shoots not grown for transplanting.  Wild plants with root systems and tops that have not been pruned are usually wide spreading, and are often tangled with roots and branches of other plants.  The main roots of wild plants may be so few and far apart, that it is impractical to excavate more than a small percentage when digging.  Their trunks, too, may be adapted to shade only to burn when moved into sun.
           
On the other hand, a nursery-grown plant usually has been pruned several times during its development, resulting in better branching close to the trunk.  Nursery plants are often "root-pruned", cutting roots with a spade around the drip line of the tree or shrub.  This results in more roots close to the trunk, meaning more roots are retained when dug.  More roots often means more successful establishment.
           
Ideally, and especially for large shrubs and trees, you should prune roots and tops from six months to a year before transplanting to increase your success.  Remove the outermost tips of main branches back to the point where side branches arise.  Avoid leaving stubs that won't heal.
           
Root prune by digging around the plant about six inches closer to the trunk than you will when transplanting.  A number of new roots will arise near the end of the cut roots.  These will better adapt the plant to its new environment when transplanted.  Root pruning is best done in early spring.  For larger plants, prune on one side early in the season, and on the other side later to reduce the shock to the plant.
           
Even before root pruning, consider the species tolerance to transplanting, the condition of the plant, and its size.  Some species are more adapted to transplanting than others.  Shrubs are generally better adapted to transplanting than trees, deciduous plants (those that lose their leaves in winter) better than evergreens, shallow-rooted plants better than ones with deep roots, and younger plants better than older ones.  Deciduous trees that transplant well include green ash, elms, hackberry, common honeylocust, poplar, sumac, and willow.  Those that transplant poorly include oaks. 
           
If a plant is weak or under stress, it will usually transplant poorly.  Large shrubs and trees may need special equipment and techniques in order to get sufficient soil and roots to transplant.  Small deciduous shrubs, and trees with a diameter less than one inch, may be moved without soil on the roots (root ball).  Larger plants should be moved with soil.  Most shrubs need a root ball diameter about two-thirds of the branch spread.  So if the shrub is 6 feet across, the root ball should be 4 feet across.  The root ball for trees should be at least 12 inches for each one-inch of trunk diameter.  A tree with a trunk two inches across should have a root ball two feet across.
           
If a plant seems too large to move yourself, contact a local landscaper.  If it is small enough, healthy, a species likely to have success, and ideally has been pruned, then make the final planting hole before digging the plant.  This ensures the plant is not out of the ground, especially if bare root, any longer than necessary.  Make the hole no deeper than you are planning to dig, and two to three times as wide.  Water the hole so the surrounding soil won't take water away from the root ball when moved, and to make sure the water will drain.  If it doesn't drain in an hour or two, break up the surrounding soil with channels or holes from a rod. If digging a deep hole, make sure to check with utilities so not to disturb buried wires and pipes.
           
When digging the plant, make sure and cut all roots.  If a larger tree, or shrub over four feet tall, trench around the plant to get under the root ball more easily.  If a clay soil, and the sides of the root ball are "glazed" or compacted in digging, roughen them up before replanting.  Make sure the plant is well watered a couple days prior to digging.  Keep lower branches tied up so they wont be injured in digging and moving.  Mark the side of tree trunks facing the sun, so they can be oriented the same way when replanting.  Otherwise bark may be tender and sunscald.  If not planting right away, keep roots and root ball covered with moist burlap or cloth.
           
Once planted, water well and then every couple of weeks if insufficient rainfall.  Mulch will help to conserve moisture.  Fertilizer is generally not needed for the first year or two, although you may water with a soluble complete fertilizer the next spring.  Prune only as needed the first year to remove broken branches, or to balance the loss of roots if the plant wilts.
           
Stake trees only if a sandy or windy site, as they generally become stronger if allowed to move with the wind.  Put a stake on each side of the tree, and use a non-binding material such as cloth to loosely tie the tree to stakes.  Wire or cord in pieces of garden hose around the trunk work well too. Remove stakes after a season or two when the tree can remain upright.   
                

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