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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