Tree Placement on Home Grounds
Christopher J. Starbuck
Department of Horticulture
Trees properly selected and placed can add more in livability and value to
the home than any other single landscape feature. They grow continually and
are ever-changing. You will never tire of looking at them.
Trees around homes provide beauty, but their more practical function is to
fulfill needs and solve problems in the home landscape.
Trees solve landscape problems by providing framing and background. Trees
also improve the appearances of our homes. They can help to absorb noise, freshen
the atmosphere, serve as windbreaks, provide privacy, protect, shade, shelter
and divide grounds into several use areas.
Home landscapes are not, and should not be, identical. Therefore, the same
kind of tree cannot be used for the same purpose on every lot. To get the most
from your trees:
- Determine the positions where trees will serve the greatest benefit.
- Select trees that will fit locations and fulfill needs best.
- Plant trees properly and give them good care and maintenance.
Functions of trees
Shade
Trees are most frequently planted for shade. The most important shade tree on
home grounds is usually located near the southwest corner of the house. If placed
properly, it will shade the house during the latter part of the afternoon in
summer. Trees provide better shade than artificial structures. Air passing through
the branches is cooled by transpiration from the leaves.
Distance
Depending on the mature size of the tree, the distance it is set from the house
will control the amount of shade given in a certain area. A tree 50 feet high
with a 30-foot spread will cast a shadow equal to the tree height at 3 to 4
p.m. in midsummer. But in winter, the shadow at the same time of day will be
120 feet long. To get the most useful shade on the house at a practical distance,
place the tree 15 to 20 feet from the house. Small trees may be planted closer
than 15 feet, but large trees should be planted 20 feet or more away from the
house.
Location
If the house faces south, or southeast, maximum shade on the front will come
from a tree that is placed to the southwest, or left front. If the house faces
southwest, a tree for maximum shade would have to be placed centrally and south
of the house (Figure 1). Make a diagram of your house and sketch trees
with their shade patterns to determine the best locations.
Figure 1
Shade patterns of a 20-foot tree during summer.
Front location
If the house is situated so that trees must be planted in the front for maximum
shade, select trees that will be high branching so that the outdoor areas can
be seen below the branches. This will also permit good air movement. The main
shade trees should be deciduous so that a maximum amount of sunlight can reach
the house in winter.
Locating small trees
Medium and small trees tend to be more in scale with modern low homes and therefore
are more in demand. Medium-sized trees can be planted 15 feet from the house
and generally 35 or more feet apart. Small trees, such as the flowering dogwood,
may be planted as close as 6 feet from the house and about 20 feet apart. Where
large trees cannot be used, several small trees may be grouped to furnish needed
shade.
Shade movement
Determine from sketches and observation where the tree should be for maximum
summer shade. Then check the shade movement of this spot. Use a long stake
or board and fix it at the selected point. Watch the shadows to determine if
your plans are right. If time permits, observe the shade pattern over several
seasons.
Remember that the shade of the house follows the same pattern as the shade
of the trees, and areas such as patios may receive a portion of their shade
from the house and not always need shade from trees.
Figure 2 shows how the angle and position of the sun change from about 26
degrees above the horizon on Dec. 21, when it is lowest in the sky, to about
73 degrees above the horizon on June 21, when it is highest in the sky.
In winter the sun moves from southeast to southwest while in summer it moves
northeast to northwest.
Figure 2
The angle of the sun during all seasons influences shade
patterns for positioning trees.
Framing
Trees planted for shade should also serve other functions. One of these might
be framing. When a house is properly framed, it appears longer and more settled
to the site. On small properties there may be room for only one additional large
tree to serve this function, while on large lots or on rural sites, two or many
trees may be used. At least two trees should be used if possible.
Tree size
Try to select trees that will be in proportion to the house. A large, two-story
house framed with small trees will appear even larger. A low house framed with
tall, broad trees will appear smaller than it actually is. At all times, select
plants and trees that are in scale with the lot as well as the house. If there
is not enough space for large trees, group small trees, or where width is a
problem, try a group of columnar trees.
Location
Trees for framing are usually planted on a more or less diagonal line outward
from the front corners of the house. This gives more apparent depth to the
lot than when trees are planted directly out to the sides on a continuation
of the front base line of the house. The effect is also better when the trees
are not planted directly opposite one another and are not of the same type.
Sometimes it is not practical to place trees at the exact spot for best framing.
If locations more directly in the lawn area must be used, select trees that
can be developed with high branching. Never plant a tree so that it will divide
any view into two equal parts or obscure the view of the house from the street
Background
A background planting of trees should be developed so that when the house is
viewed from the front, the tops of the trees can be seen above the roof line.
This softens the roof line and makes the house easier to see.
Tree types
When there is space for more than one background tree, do not use the same types
of trees. One tree should be used that develops taller than the others. An
irregular tree line above the roof line is most desirable. Where possible,
trees with relatively fine-textured leaves, such as birch or honeylocust, will
provide the most pleasing backgrounds. Medium to fine textures in leaves and
branches give the illusion of more depth to limited areas.
If space limitations permit use of only one or two trees that must be centrally
located, select trees with tall trunks so that pleasant views will not be hidden.
Location
Placement of trees for background will often be influenced by other needs. If
the back of the house faces west or southwest, these trees may be important
for shade. In this situation, the trees may be needed fairly close to the house.
In other places, these trees may be needed to block undesirable views. Then
it may be necessary to place them near the property line. Background trees
should serve a dual function as much as possible.
Accent
Small trees with attractive flowers, berries, leaves or bark are often helpful
to provide accent and complete the picture. Except on very large properties,
an accent tree should be a small one, although any tree provides some accent
in the landscape. Small trees may also be used on large properties but should
be grouped for a more striking effect.
Location
Specimen trees for accent must be used sparingly. Too many of them will add
confusion to the landscape. If planted out from and to one side of the front
entrance, a specimen plant can focus attention on the front door.
The small specimen tree can also be useful as a part of entrance plantings
when combined with shrubs and groundcovers at a driveway entrance.
In shrub borders of the backyard, accent trees will provide a focal point
for different areas. Place them with other features, such as pools or benches,
that may terminate a line of sight from the house. In the flower or shrub border,
locate them where curves are sharp. At this point, the eye tends to slow as
it follows the border and is attracted to the accent. On a small lot, one specimen
for accent in the backyard is usually sufficient. On large lots, several can
be used, but avoid confusion. When accent trees are included in a border, the
mature height of the tree should be approximately 1-1/2 times as the bed is
deep. Therefore, a bed 10 feet wide should contain a tree that gets more than
15 feet high.
Because most people use specimen plants for their own enjoyment and to satisfy
personal preferences, the positioning should also take into consideration the
view from the house. Whenever a specimen is used, it should be placed so that
it can be seen from inside the house. It should be placed so that it will terminate
a major line of sight from windows of rooms most used in the house. Trees with
decorative bark or berries in winter should especially be used in these positions.
Screens
The view of unsightly areas needs to be blocked from the home. Tree screens can
provide needed privacy and at the same time may establish a sound barrier or
windbreak. Trees provide more rapid screening than many shrubs. If a year-round
screen is desired, evergreens should be used.
Trees do not have to be in a straight line to develop a screen. Often a grouping
of trees will provide needed screening without giving a stiff appearance.
Plan the entire planting at one time even though other factors may make it
necessary to plant over several seasons. Unless the property is large, tree
screens will usually have to be composed of small or medium-sized trees. If
space is very limited, columnar trees may be used to make an effective screen
with a minimum of width. A screen of trees gives more interest and variety than
a fence or other artificial screens. Different types of trees may be blended
together to avoid monotony in screening.
Coniferous evergreens are desirable for a year-round screen. Their distinctive
shape and texture make them dominant in plantings. For this reason they should
be used sparingly.
Other considerations
Always consider he ultimate size of the tree before planting. Failure to do so
leads to escessive shading, increased pruning requirements and root problems.
- Do not plant trees near underground pipelines, septic tanks, walks or drives
or under overhead wires. Check with your local utility companies for the location
of buried utility lines
- Do not plant a tree where it will overhang the house, in front of the front
door or where it will obstruct a desirable view from inside the house.
- Do not plant a large tree closer than 5 feet from a sidewalk; it will eventually
push up the concrete.
- Do not plant trees closer together than half their total spread at maturity.
- Do not plant trees closer than 25 feet from the corner of a block so that
they will not interfere with motorists' vision at intersections.
- Do not plant trees directly on property lines.
- Do not plant trees that give dense shade where you want to grow grass.
Planning with existing trees
When homes are built in a naturalistic setting on a wooded lot, there is often
reluctance to remove any of the trees. Failure to select carefully at the time
of construction may result in many problems later.
Remove any trees that are diseased, injured or deformed. If trees overhang
the house, they present a safety threat and should be removed or pruned. If
gardens are desired and the shade is too dense, remove enough trees in the selected
gardening site to let in sufficient light. Remember that existing trees grow
and will need to be pruned later to keep this space open.
Clean out brush and trim up the trunks of the trees in the front area so
that the house can be viewed from the street by looking between the trunks of
the trees. Along property lines, shrubs should be allowed to remain or added
to develop privacy.
A lot may not have enough trees on it for a naturalistic effect. Where only
a few exist, the first step should again be to remove misshapen, diseased, damaged
or poor trees. From those remaining, select the best to fulfill needs such as
shade, framing or background.
Selecting the tree
After the need for a tree at a given location has been established, the next
step will be to determine what tree or trees would best satisfy the needs. Several
characteristics of trees must be considered.
Size
Trees for use in the landscape are usually classified as small, medium and large.
Size categories may overlap depending on culture and climatic conditions.
- Small trees
Those that rarely reach a height of more than 25 feet.
- Medium trees
Those that mature at about 40 feet.
- Large trees
Those that mature at heights greater than 40 feet. Some
may reach heights of 75 to 100 feet.
In the landscape, large trees are in scale with tall houses but will make
low houses seem smaller. Small and medium trees fit well with low trees but
will make a tall house appear even taller.
Shape
The natural shape of a tree will influence its appropriateness to many landscape
uses. Choose a form that will suit your needs and then find types or varieties
with these forms.
Erect, columnar fastigiate
Trees with upright, slender growth that produce a towering effect. These trees
are useful for accents in mass plantings and will accent vertical lines of
buildings. They are useful for large screens and windbreaks where land space
is limited.
Some trees of this type are the pyramidal English oak, columnar red maple,
columnar European hornbeam, buckthorn, the short-lived Lombardy poplar and many
columnar junipers.
Spreading
Trees with a broad, natural growth and horizontal branching habit. They often
form flat tops. They are useful for breaking vertical lines in buildings. Examples
of trees with this growth are hawthorn, golden rain, dogwood, flowering cherry
and mimosa.
Open-headed
Trees with a rather indistinct outline and a loose, open structure. Their value
in the landscape is a tracery against the sky and light shadow cast on the
ground. Large trees in this group make good trees for background planning.
Typical examples are honeylocust and mature ginkgo.
Round-headed
Trees with curving or rounded crowns. They are often close-branched and provide
dense shade. Trees of this type are dominant and produce a dense textural effect.
Examples of this type are the Norway maple, catalpa and saucer magnolia.
Pyramidal
Trees with a single stem, from which branches grow at right angles and appear
to be in layers. In outline the tree has a cone-shaped effect. The form is
very dominating and therefore these trees are best used as specimens or grouped
in mass plantings. Sweet gum, pin oak, American holly and spruce species are
examples of trees with this type of growth.
Oval
Trees with a general egg-shaped appearance. Top of the growth comes to a broad
point which may be rounded. The overall crown is not as broad as the round-headed
shape. Many trees of this type provide dense shade and become dominant landscape
trees. Examples are sugar maple and horse chestnut.
Umbrageous (umbrella-shape)
Trees with a rounded top, but open-headed growth to form a canopy that suggests
an umbrella. The vanishing American elm is an example of a tree with this type
of growth. Hackberries and zelkova also have this growth habit. They are especially
useful in areas where shade is needed but where low-branching trees would obstruct
views. This type of growth allows good light penetration beneath the trees.
Weeping
Trees with branches that hang freely toward the ground from the trunk or other
branches. The form is rather unnatural and trees of this type should be used
only in flat areas where the eye is directed downward toward some interesting
feature such as a pool. Their use should be limited to that of an accent plant.
Very popular, although easily broken in storms, is the weeping willow. Weeping
forms of many trees have been developed such as the weeping birch, weeping
beech and weeping cherry.
Texture
In leaves, stems and twigs, trees possess definite textural qualities. These
qualities should be related to surrounding items and plants.
Trees with coarse leaves, large branches and dense growth are dominant. Large
trees of this type dwarf things around them. They are best suited to large areas
and to large homes and buildings. Small trees of this type make striking accents.
Coarse textures give a feeling of closeness. This type of tree is most useful
as a noise barrier.
A tree with medium texture can relieve the heaviness of many buildings and
give a greater feeling of space. Trees of this type allow good light penetration
and air movement and still provide good shade and screening.
Fine-textured or filamentous trees are more open and light penetrates them
well. Twigs, foliage and branches are usually small and slender. The feathery
foliage is valuable for small areas since it helps to produce a feeling of space.
Large plants of this type help to give a greater feeling of depth to small areas
when used behind plants of coarse texture.
Other characteristics to consider
- Do not select trees to be put close to the house that are rapid-growing
but short-lived and prone to breakage from ice, snow or wind.
- Select trees with few or no insect or disease problems. If trees are chosen
with known problems, be prepared to give adequate control measures.
- Choose trees that are hardy for the area.
- Choose trees that are in scale with the house and site.
- Avoid trees with messy fruit, seed pods and frequent shedding of twigs and
small branches.
- Select trees suited to environmental conditions of the area such as summer
heat, air pollution, drainage and soil.
G6900, revised October 1999