TRANSPLANTING TREES AND SHRUBS
W.M. Fountain, C.A. Kaiser, M.L. Witt, J.R. Hartman
"He who plants a tree plants hope."
Properly planted trees or shrubs offer a great deal of satisfaction and
aesthetic appreciation to the person planting and caring for them. Besides
giving you the joy of watching them grow with each passing year, trees
in the landscape will reduce your heating/cooling budget, increase your
home's value and make selling it easier. Trees and shrubs are also valuable
for adding privacy and attracting wildlife to the neighborhood. Unfortunately,
you cannot start out with mature specimens. The care taken at planting
and in the early years will determine what the tree or shrub looks like
at maturity, if indeed it makes it to maturity.
Types of Nursery Stock Available
Woody plants are produced and sold
in 3 different forms: container- grown, balled-and-burlapped and bare-root.
Each has its own unique characteristics and planting requirements and no
one type of purchase is always best.
Container-grown trees and shrubs
are generally much smaller than balled-and-burlapped plants. They are well-established
in the container and may be kept easily until planting time as long as
they receive a daily watering. Container-grown plants are less expensive
to ship because they are grown in light-weight, artificial soil. Another
advantage is that the root system is completely intact because the plant
has grown in the container since it was a seedling. A disadvantage to container
grown plants is that once planted in the landscape, roots are often slow
to break out of the artificial mix into native soil. Also, artificial mixes
dry out much more rapidly than surrounding soil, so watering is very important.
The root system of a balled-and-burlapped
plant is cut when it is dug at the nursery. The root ball is usually wrapped
in burlap or placed in a wire basket in preparation for sale. These plants
need to be kept in a sheltered place outdoors until they can be planted.
While balled-and-burlapped plants can be held for short periods of time
after purchase, the sooner they are installed, the better. They are heavy
because of their large soil/root ball, so shipping them for long distances
is not economical. Therefore, chances are your balled-and-burlapped plant
was grown in a nearby nursery. However, the weight makes the plant difficult
to handle. You must dig a hole to the correct depth before lowering the
plant into it. Often these plants are too heavy for one person to lower
into the hole and you may need help. Never drop the soil ball into a hole
since it will crack and break roots. Also, never pick up the plant by holding
the trunk -- the roots cannot support that much weight.
Bare-root plants are normally
kept in cold storage (40o F) until they are sold. Prompt planting
while the plant is still dormant is important. Roses, fruit trees, hedges
and perennials are commonly sold as bare-root plants. This method of shipping
plants long distances is cheapest and results in the greatest savings for
the customer. A disadvantage to bare-root plants is they suffer a great
deal of root loss when they are dug and soil is removed from their roots.
Because of this loss, bare-root plants must be handled with more exacting
Proper Planting Techniques
Special Handling Required Before Planting
The major site of root regeneration
is the severed root end of balled-and-burlapped plants. Consequently, take
care to keep roots, especially outer root ends, from drying. Keep the soil
ball moist until the tree or shrub is planted, but never leave the plant
standing in a tub of water. A thorough soaking with a hose usually works
Bare-root trees and shrubs have a better
chance of survival if you plant them in the spring before their active
growth starts. Never allow the roots to dry out because they will die.
Dampened sawdust, loose compost or potting mix are packed around plants
before shipping and should be kept moist at all times. If bare-root plants
cannot be planted immediately after purchase, they can be "heeled-in."
To do so, make a bed of damp, well-aged sawdust or loose compost 8-24 inches
deep and put the plant's roots in it until planting. During dry periods,
the beds need to be watered. Before planting, soak roots in water for 30
minutes while you prepare the hole.
Selecting the Site
The growing site should be carefully
selected. Consider not only where the plant will look good, but also where
it will grow successfully. Be sure the tree or shrub will be able to reach
full maturity without growing into overhead wires, buildings, fences, other
plants, driveway areas, etc. Choose a site where soil is deep, fertile
and well-drained. Trees and shrubs growing in soils poorly drained due
to compaction, high clay content or rock near the surface will have problems
with surface roots, lack of hardiness, poor leaf color and fall color,
limited stem growth, limited flowering, and diseases and insects. Sun and
wind exposure should also be taken into account before planting.
Raised Beds -- One solution
to landscaping poorly-drained soils is to plant in a raised bed. The bed
must be deep enough to contain the plant's roots. The root system of a
tree obviously will occupy a greater volume than a small shrub's. A general
rule of thumb is to use a depth of at least 18 inches for small shrubs
and 30 inches for trees. The raised bed area should extend to the tips
of the farthest branches (the dripline) of the plant being installed. Realistically,
you should expect to replace trees in raised beds every 15 to 20 years.
The root system will have filled the bed by then and the plant's height
will make it less stable in storms.
Dig the Hole
Size - The planting hole should
be large enough to accommodate roots without twisting and breaking either
the roots or the soil ball. The hole for balled-and-burlapped and container-grown
plants should be as deep as the root ball. Bare-root plants require a hole
that is slightly deeper than the root system.
What to Dig With - Hand digging
the hole with a shovel is the best method. Whenever an auger or posthole
digger is used, the sides of the hole are likely to be slick. If so, use
a spade or other tool to scrape and loosen the sides of the hole. Also,
soils high in clay should not be dug when they are wet because the metal
shovel will leave the sides of the hole slick like the side of a glazed
Roots must be able to penetrate all
sides of the planting hole, but if the surface is glazed, most of the roots
approaching this layer will be unable to grow through it to establish roots
in the surrounding soil.
Remove Damaged Roots
Remove broken, dangling roots from
container-grown and bare-root plants. Make clean cuts using a sharp knife
or pruning shears. Similarly, diseased roots and dead root tips should
be removed past the point of damage. Damaged root tissues are a good entry
site for root-rotting fungi. In addition, cutting these roots back will
Remove Packing Materials (If It Doesn't Rot, Remove It)
Metal or plastic containers must be
removed from container-grown plants prior to planting. Tap the container
on the bottom and sides to loosen it from the soil ball.
All nursery tags and the string, twine
or wire used to attach them to the trunk or branches should also be removed.
Some balled-and-burlapped plants are
prepared using synthetic or plastic burlap. These materials have been used
in the nursery industry when plants have to be held for more than a couple
of weeks. It does not rot on top of the ground and it will not rot under
ground. Roots are not able to go through the plastic and, if it is not
completely removed, the plant will be pot-bound in the landscape. In addition,
metal baskets and twine should be removed from the root ball prior to planting.
These materials, if left on, will result in girdling as the roots enlarge.
If the burlap is biodegradable (usually
tan in color with no hint of plastic), it may be left on the ball. However,
some synthetic burlaps superficially look and feel like burlap. If you
are unsure of the nature of the fabric, remove it or cut it away from the
root ball. Be sure, also, to remove the plastic string or twine which secures
the burlap and is wrapped around the trunk. It is also a good idea to pull
the burlap away from the trunk. Nursery nails used to secure the burlap
do not have to be removed.
Spread Out the Roots
Roots of bare-root plants should be
spread out in the planting hole. Cramming all roots into the bottom of
the hole will turn them and can result in girdling root problems in years
If container-grown plant material is
root-bound at transplanting, roots may continue to spiral within the planting
hole. To prevent this, the mass of roots that encircle the container should
be cut or disturbed by pulling them apart. This action prevents continued
circling that can later develop into girdling roots. Using a sharp knife,
make vertical cuts one inch deep at 4 to 6 different locations around the
Plant and Backfill
Roots must have oxygen to take up water
and mineral nutrients from the soil. The deeper you go in the soil, the
less oxygen there is, so roots must be planted at the same depth they were
previously grown. Look for a fairly abrupt change in color near the base
of the trunk to determine the previous soil line and plant at that depth.
You may plant it slightly shallower, to allow for settling.
If the hole is dug too deep, soil can
be added to the bottom of the planting hole, but make sure that soil is
After you put the tree or shrub into
the planting hole, place some topsoil around the roots until the hole is
half full. Tamp lightly and water thoroughly. After water has filtered
down and settled the soil, fill the remainder of the hole with topsoil
and water the new planting thoroughly.
Fill Soil - Generally, the best thing
to put back in the planting hole is the same soil that came out of it.
Soil amendments (such as peat moss, pine bark, etc.) are expensive, difficult
to mix evenly and do little to
help the plant establish itself in its new location. Often roots will
grow very well in amended soil, but fail to penetrate the side wall of
the planting hole.
If an entire bed is being prepared,
amending heavy soils to provide improved aeration and water movement will
improve root growth.
Soil amendments are necessary when
planting rhododendron and azalea beds. Mix sphagnum, peat moss thoroughly
into the planting area using a 1:1 ratio of peat moss to soil. Raised beds
are often built for these plants and large amounts of peat moss are incorporated
into the entire area to keep the soil pH around 4.5 to 5.0.
Adding a layer of mulch (bark, wood
chips or stone) three inches deep will help control weeds and conserve
soil moisture. Black plastic mulch is good for annual plantings, such as
annual flower beds and vegetable gardens but should never be used for perennial
beds, because the roots under the plastic cannot get enough oxygen. Roots
grow poorly and plants decline prematurely when insufficient oxygen is
available. Some of the new fiber mulches may overcome this problem.
Staking Is Usually Unnecessary
Trees and shrubs should be staked only
when there is danger that they will be blown over by high winds. Trunk
diameter and strength usually increases faster in unstaked plants that
are allowed to move with the breeze. Root development is also faster for
Even though staking is not recommended,
especially for small trees, if you think it is necessary for particularly
top-heavy trees, be sure to place stakes correctly. While two or three
stakes can be used, we recommend using three. Using a single stake is not
recommended since it can rub against the trunk, causing injury.
Put stakes outside the planting hole
area, where the ground is firmer, and far enough into the ground to prevent
their being pulled out. Whether stakes are short or long, attach securing
lines about two thirds of the way up the plant. Use metal wires to guy
the tree. An old piece of rubber hose around the wire will protect the
tree from being girdled. If the tree is large, use turnbuckles on each
of the wires to take up slack. It is generally not necessary to leave staking
in place after one year. Check wires frequently since loose wire can rub
the trunk and excessively tight wires can girdle it.
Wrap the Trunk
Newly transplanted trees are often
wrapped as a routine practice with one of the commercially available wrapping
materials to protect their thin bark from sunscald. Research indicates
that sunscald occurs on young trees with severed or crowded roots because
they are not able to take up sufficient amounts of water. Wraps help reflect
sunlight and add an extra layer of insulation against sudden temperature
changes that can occur in winter. Begin wrapping at the base of the trunk
and continue up to the first branches. Overlap each of the previous layers
so that water will be shed. Wrap trees during the fall after planting and
remove the wrap the following spring. A loose cylinder of screen may also
be used effectively as a tree wrap. Leaving tree wrap on for more than
one season has been shown to increase borer infestations on some species
and may also lead to decay of the bark.
Regular Watering is Essential
The effect of extensive root loss must
be considered when transplanting bare-root and balled-and-burlapped trees
and shrubs. Less than 10% of a tree's root system remains in an average
root ball and even fewer roots remain on a bare-root plant. When a substantial
portion of the root area is lost, the plant's capacity to take up water
is also significantly reduced. As a result, transplanted trees and shrubs
can experience considerable water stress.
Watering, then, is the single most
important thing you can do for a newly transplanted tree. Trees and shrubs
not receiving one inch to two inches of rainfall per week will need supplementary
watering during the first year after transplanting. In fact, you will need
to continue regular watering for 3 years, because trees and shrubs may
take that long to become fully established in a landscape.
Supply enough water to soak the soil
around the roots at each watering and allow the soil to dry between waterings.
A good practice is to thoroughly soak the soil every 7 to 10 days during
dry periods. Avoid frequent light waterings since this encourages root
growth near the soil surface.
Needled evergreens (e.g. pine, spruce)
and broad-leaf evergreens (e.g. rhododendron) keep their leaves during
the winter. Because they continue to lose water through their leaves during
this time, evergreens should also be watered during dry periods in the
winter as long as the ground is not frozen. Deciduous plants (e.g. maple,
oak) are dormant in winter and generally do not require watering during
these months. However, winter watering for deciduous plants will be necessary
during winters with little or no rain or snow.
Balance the Top to the Roots?
For years the rule has been to prune
tops back so the above ground portions of the plant will be in balance
with the root system. While it is true that a large portion of the root
system is lost with newly transplanted material, you generally do not need
to remove any branches. Leaves are vital to making sugars that provide
energy for forming new roots.
Corrective pruning, however, may be
necessary. Dead, damaged or misshapen branches can create problems later
and should be removed at planting time. Do not remove the central stem,
do not leave stubs and never top the tree. In short, follow good pruning
Allow the plant to remain in its new
site for a year before fertilizing. Plants generally do better if allowed
to recover from the initial shock of transplanting before fertilizer is
applied. Soils capable of supporting growth over a period of years are
more than fertile enough to satisfy the plant's demands the first year.
The goal during the first year is re-establishment
of the root system, and not promotion of growth to the plant's above-ground
portions. Fertilizer can actually cause production of more leaves than
the root system is capable of supporting.
If someone insists on using fertilizer
immediately after transplanting, a water-soluble formulation high in phosphorous
and low in nitrogen would be best. This type of fertilizer is commonly
used for all types of transplants.
During the fall following transplanting,
apply 1/3 lb of ammonium nitrate or 1 lb of 10-10-10 per 100 square feet
of root area. In successive years, this amount can be increased to 2/3-1
lb of ammonium nitrate or 2.3 lb of 10-10-10 per 100 sq ft root area. If
your lawn is being fertilized, there should already be a sufficient amount
of fertilizer available to the tree roots.
Whenever a tree or shrub is moved from
one growing site (e.g. a nursery) to another (e.g. your landscape), it
is stressed. When great care is taken to minimize stress through proper
transplant techniques and maintenance, the plant is likely to recover rapidly
and become well-established in the new site. Unfortunately, all too often
the opposite occurs-the tree or shrub suffers "transplant shock' from careless
or improper transplant methods, and recovery is hindered. Poor growth,
wilting, yellowing, premature leaf or needle drop and dieback are typical
symptoms of transplant shock. Trees or shrubs unable to recover, continue
to decline and eventually die.
A tree or shrub may take as long as
3 years to recover from transplanting stress. Even with good root regeneration,
the transplant often will not show much top growth until roots reach their
original expanse prior to digging. Failure of the plant to regenerate new,
healthy roots or to establish its root system in the new site is frequently
the underlying cause of transplant shock. Such root-related problems may
be traced to one or more factors: stresses that occurred when the plant
was removed from the original site, injury in transit, improper planting
techniques and/or poor cultural practices.
Some of the specific causes of transplant
shock and related problems are listed below:
Poor Plant Material
•Species not hardy in Kentucky.
•Plant not healthy and vigorous.
•Root ball too small for the amount
of top growth (often leading to sunscald).
•Plant roots not kept moist between
digging and transplanting.
•Leaves of plant not protected from
wind during transport from nursery to home landscape.
Undesirable Growing site
•Soil poorly drained (e.g. subsoil
or other high clay content soils).
•Planted near a downspout or in a depression,
resulting in wet feet problems.
•Extremely compacted soil in planting
•Shade-loving tree or shrub planted
in full sun, or vice versa.
Poor Transplant Techniques
•Root ball allowed to dry out before
•Root ball allowed to freeze prior
•Mechanical injury during digging,
moving or transplanting.
•Hole dug too small, crowding roots.
•Sides of hole "glazed," preventing
further root penetration.
•Twine or wire holding nursery tags
left on, girdling the tree.
•Plastic (non-biodegradable) "burlap"
or twine left around the root ball.
•Container grown plant is root bound,
and roots continue to grow around in a spiral, rather than growing outward.
•Planted at the wrong depth, either
too deep or too shallow.
•Tree wrap left on trunk longer than
through the winter.
•Excessive use of fertilizer at planting,
•Turfgrass growing too close to the
trunk (no mulch used), an invitation to injury from mowers, string trimmers,
Poor Follow-up Cultural Practices
•Improper watering - little or no watering,
excessive watering (especially problematic in heavy clay soils), or frequent
•Application of high levels of nitrogen,
resulting in excessive top growth compared to the root growth.
Prevention is the key to minimizing
transplant shock. Only healthy, hardy landscape material should be planted
using the techniques described above. Take the following steps if your
tree or shrub is already planted and now showing transplant shock symptoms:
1.If the tree or shrub needs
to be moved to a better site, do so.
2.Alleviate or correct as many
stresses as possible.
3.Prune out dead and dying branches.
4.Water thoroughly with the
equivalent of 1-2 inches per week during dry periods.
5.Fertilize as described above.