of Rhode Island GreenShare Factsheets
for Sustainable Landscapes
Giving plants a healthy start begins with proper planting.
Problems showing up on established plants can often be traced
back to poor planting. Traditional planting methods are often
passed down through the generations. While some of the old ways
are still recommended today, many planting practices are changing
to reflect current research and technology. Well-informed landscapers
and arborists should be aware of the latest planting and transplanting
techniques. This chapter presents the techniques and procedures
used to plant and transplant trees and shrubs, and explains how
the use of proper planting techniques can improve survival and
A key to sustainable planting is matching
the plant and the conditions of the planting site. The best planting
procedures will not save a plant that is poorly suited for the
site. Plants vary naturally in their ability to tolerate site
conditions such as extreme heat or cold, wet or dry soils, sun
or shade. The plant also should not outgrow its allotted space.
Plants should be healthy and vigorous when planted. The condition
of the roots in particular affects trans- plant success. The
roots should be white and numerous; brown or black roots indicate
a health problem.
Trees and shrubs are available from the nursery in one of
three forms: bare root, balled and burlapped, or container grown.
Depending upon site requirements and planting specifications,
each form has its advantages and disadvantages. Bare root plants
have had the soil shaken from their roots after digging. Most
bare root trees and shrubs are purchased by mail order and planted
during the dormant season, before roots and buds begin to grow.
Since there is no soil on the roots, it is vital that they be
kept moist, and if not planted immediately, that they be stored
cold (32 to 40 degrees F) with moist packing around the roots.
When planted, the roots of bare root plants should be spread
evenly in the planting hole.
Container grown plants have been grown for months or years
in the container in which they are sold. Container growing is
becoming very popular in the nursery trade. Container grown plants
may be planted anytime the soil is workable, but may need special
attention to correct compacted or circling roots. When selecting
container grown trees and shrubs, always check the roots. For
example, not all plants purchased in containers are container
grown. Often bare root trees or shrubs are potted in containers,
grown for a short time and sold from the nursery. If they are
not held for at least a year, the roots may not have established
in the container. On the other hand, if plants are grown in their
container for too long, the roots may have grown in circles.
These roots must be separated and spread out during planting.
If the roots are densely matted, the outside of the root mass
should be sliced vertically with a sharp knife in a few places
to help separate the roots. And unless the container is biodegradable,
such as a natural peat pot, it must be removed before planting.
If properly watered and maintained, container grown trees
can be planted any time of the year. Early fall planting is especially
advantageous because the roots can begin to establish before
the plant goes dormant for winter. Early spring, before bud break,
is also a good time to plant because the roots begin to grow
immediately, and light, temperature and soil moisture levels
are optimal. Perhaps the most important factor in successfully
transplanting container grown trees is maintaining adequate (not
excessive) soil moisture, which encourages roots to grow into
the surrounding soil.
Many trees and shrubs are dug in the nursery with root balls
intact and wrapped with burlap. Be aware that as much as 95%
of the absorbing roots can be lost in digging, though some roots
are preserved in the root ball. When selecting a balled and burlapped
plant, be sure the ball is solid, with little or no movement
of the trunk. The burlap used to wrap the root ball holds the
soil ball together and keeps the roots from drying out. Natural
fiber burlap is biodegradable and may be left in the hole, though
it should be rolled back and completely covered with soil. Some
nurseries use treated burlap or synthetic burlap which must be
removed at planting. All twine or rope holding the burlap together
or tied around the trunk must be removed to avoid girdling. Some
larger balled and burlapped trees come in wire baskets that keep
the ball together during handling. Although the baskets do not
have to be removed, it is best to cut the upper rows when planting.
This eliminates interference with rakes or lawn mowers if the
tree is planted shallow, and allows roots to grow and spread
freely near the surface.
Installing trees and shrubs properly involves more than
just digging holes and setting in plants. The quality of the
planting hole will determine the long term health of the root
system, and thereby the entire plant. In general, the planting
hole should be at least 18 to 24 inches wider in diameter than
the root ball. If the soil is compacted or of poor quality, the
hole should be even larger, i.e. three to five times the width
of the root ball. The hole should be wider at the top than the
bottom, with sloped walls, because most of the root growth will
be shallow and horizontal. Planting too deeply can stress the
plant and drown or suffocate the roots. The easiest way to avoid
this is never to dig the hole deeper than the root ball. Soft
fill should not be left in the bottom of the hole, as the root
ball will settle. In almost all types of soil, the tree should
be planted slightly shallow, with the top 2-3 inches of the root
ball sitting above the surrounding soil grade. Remember, the
planting site will be covered with 2-3 inches of mulch by the
time you are finished planting.
Drainage is also an important consideration in successful
planting. Poor drainage kills more plants than any other cause.
A poorly prepared planting hole may act as a dish and hold water,
especially in clay soils. Oxygen levels are low in the bottom
of such holes and not conducive to healthy root growth. Do not
put gravel in the bottom of the planting hole; it does not aid
Handle roots carefully during planting┬small
absorbing roots are easily broken. Check balled and burlapped
ensure the roots originate near the surface of the ball. When
setting the plant in the hole, make sure these roots are no deeper
than the soil grade.
In most cases, it is best to backfill the hole with the
same soil that came out of the hole. Research has shown that
soil amendments usually do not improve plant establishment or
growth. However, if the natural soil is extremely poor, topsoil
may be the only alternative. Strive to match the backfill soil
type to the soil type of the site, as closely as possible. Backfilling
with a sandy loam in heavy clay soils may cause the planting
hole to collect water and suffocate the roots. If soil must be
brought to the site, or the backfill must be amended, the hole
should be extra wide. This will allow for several years' growth
within the new soil. While backfilling, work the soil around
the ball so that no air pockets remain. Large pockets of air
can allow roots to dry out. Firm the soil so that the plant is
vertical and adequately supported, but do not pack the soil.
Water thoroughly while backfilling. The remaining soil should
be mounded into a berm, on the outer edge of the hole, to collect
water over the root zone, especially on sloped sites. Remove
all tags or labels so that they will not girdle the trunk or
branches as the plant grows.
After filling the planting basin with water and letting
it drain, fill the basin with 2 to 3 inches of an organic mulch.
This will conserve soil moisture, moderate soil temperature extremes,
and reduce competition from weeds and turf. Many organic mulches
such as pine needles, bark or wood chips are fine. Make certain
the mulch is not touching the plant stem, as this could promote
bark decay, crown rot, winter injury or rodent damage. Do not
use black plastic or landscape fabric under the mulch, since
these materials, sooner or later, restrict water movement and
oxygen availability to the roots.
Planting is a major operation from
which most trees and shrubs recover slowly. A major portion
of the root system is
lost in digging, and the plant must reestablish sufficient roots
to sustain itself. During this period, the plantís ability to
obtain and transport water and minerals is greatly reduced, which
results in varying degrees of water stress and transplant shock.
For this reason, proper watering is key to the survival of newly
planted trees and shrubs. If rainfall is not sufficient (generally
1 inch per week), the tree should be watered every five to seven
days. A slow gentle soaking of the root zone is preferable. The
watering schedule should be appropriate for the soil type and
drainage┬remember that excess water in the planting hole is a
leading cause of transplant death.
Since the root system functions of a newly planted tree
are limited, fertilization often is not recommended at the time
of planting. Excessive fertilizer in the root zone can be damaging,
so do not add fertilizer to the backfill. If fertilizer must
be used at planting or in the first growing season, apply a controlled-release
fertilizer or liquid feed. Fertilizing in the fall when the roots
are active can be beneficial. However, most plants received from
the nursery require no fertilizer in the first year of establishment.
Plants grow and establish fastest if pruning is minimized
at planting. Beyond the removal of broken or damaged branches,
it is usually best to avoid heavy pruning.
Most shrubs do not need to be supported after planting.
In general, trees under 8 feet height do not need support either.
In fact, staking can have detrimental effects on the development
of trunk taper and root growth. Too often, staking materials
end up injuring or girdling the tree.
Trees may be supported by up to three stakes. If a single
stake is used, it should be placed on the upwind side of the
tree. The material used to attach the tree to the stake should
be broad, smooth and somewhat elastic. The tree may be attached
to the stake at several points along the trunk. However, do not
stake the tree too rigidly, as the tree will develop a less sturdy
root system and be more subject to girdling. If two support stakes
are used, a single, flexible tie attached to the tops of the
stakes will be sufficient. Triple staking provides more protection
against strong wind and lawn mowers. Support stakes and guy wires
generally should be removed after one growing season. If staking
is left in place for more than two years, the tree's ability
to stand alone may be reduced and the chances of girdling injury
Planting guidelines are based on information
found in the International Society for Arboriculture Arboristís
Certification Study Guide, the Penn State University Master
Gardener Manual and Arboriculture: Integrated Management
of Landscape Trees, Shrubs and Vines by Richard W. Harris.
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
of Rhode Island Cooperative Extension provides equal program