


Small Trees for Home Landscapes
Marianne C. Ophardt
Washington State University Cooperative Extension
Area Extension Agent
Plant small trees.
Of course, most trees are relatively small when planted in the home
landscape, but only “small” trees stay a reasonable height for the normal
home landscape. According to Dr. Ray Maleike, WSU Extension Horticulturist,
smaller trees generally require less care than larger trees.
He says, “Small trees can be chosen so that they remain in bounds,
have multi-seasonal interest,... and are hardy, resistant to pests, and
drought tolerant.” He points out that when small trees do need care, such as
pruning, irrigation, fertilization and spraying, the task is much easier
because the tree isn’t so tall.
Larger trees also often create problems with
their root systems. The roots of
larger trees tend to be more invasive, causing problems with sidewalks,
driveways, and lawns. It’s prudent to note that the roots of a tree
frequently extend as far from the trunk as the tree is tall.
This root growth can be quite rapid, with the roots growing to three
times the branch spread within two to three years after planting.
Just imagine how far out the roots of large shade trees, with crowns
that grow to heights of 50 to 80 feet, will reach!
The smaller the tree, the smaller the root problem.
Smaller trees seldom require extensive
pruning to keep them in bounds. Usually
only minimal pruning ... to enhance the shape or remove limbs with undesired
placement... is needed. Large
shade trees tend to outgrow their space in the landscape and can require
costly, extensive pruning as they grow older. Even large trees don’t “need” pruning except to remove
dead or damaged wood. However,
pruning is frequently necessary to keep large trees within a reasonable size
for the home landscape and to avoid problems with overhead utilities.
While there are a number of lovely shade
trees available for use in the home landscape, few offer the seasonal interest
that smaller specimen trees display... such as spring flowers, fruit and fall
color. Attractive bark and winter
silhouettes are also desirable characteristics.
When selecting any type of tree you should
consider:
- Mature size of the tree. Is the tree
suited to the site and home design? A large shade tree must be sited where it will provide the
shade needed and where its roots won’t cause problems. The proximity to overhead and underground utilities, septic
systems, swimming pools, building foundations, and paved areas should be
assessed. In many situations you want to select trees that don’t grow
too tall because they could block a desirable view from your home.
- Pest resistance.
Small or large, it’s always a good idea to select a tree that’s
not prone to insects or diseases. This
is important in reducing pesticide use and lowering the maintenance time
required to keep a tree healthy. Avoid
pest-prone trees that will require lots of attention, such as white birch
which is frequently attached by bronze birch borer or some varieties of
flowering crab apples which are bothered by powdery mildew.
- Adaptable to the climate and environment.
Many gardeners persist in planting trees not well suited to a
particular area. Trees should
be winter hardy to UDSA Zone 6 and able to withstand the summer heat
stress experienced in this region. Trees
that are marginally hardy or prefer milder summers, such as vine maple or
quaking aspen, are harder to grow successfully here.
It’s upsetting to grow a tree for several years and then have it
damaged or killed during a cold winter or stressed by hot summer weather.
- Adaptable to site.
Pick a tree suited to the soil conditions and site that has been
selected. Trees that do
better with in a protected location with some afternoon shade, such as
flowering dogwood or Japanese maple, should not be placed on the south
side of a building surrounded by concrete and rocks.
- Trees with seasonal interest.
Many trees, especially the smaller trees, offer seasonal interest
to the landscape... flowers in the spring or summer, fragrance, fall
color, fruit, interesting bark, or distinctive winter form.
Don’t just settle for nice green leaves in the summer, select a
tree that will provide you with appeal all through the growing season.
Favorite Small Trees for Our Region
Flowering Dogwood (mature height 15'
to 25' depending on the cultivar) - this is a favorite small tree of many
gardeners but it’s not really well adapted to our summer climate and often
suffers summer leaf scorch from extended spells of 90+ degree weather. While
it’s difficult to establish in this area, once it’s growing well it seems
to thrive here. It has wonderful
white flowers in the spring and a rich red fall color with bright red berries.
It should be planted in a protected location.
Japanese Maple (mature height 6' to
20', depending on the cultivar) - another favorite gem of gardeners
everywhere, but it’s also generally not well adapted to our summer climate
or soils and often suffers from leaf scorch when not placed in a protected
site away from hot summer sun and wind. In
the right place this can be the most beautiful tree anywhere.
It may not have remarkable spring flowers, but it’s delicate
dissected leaves and fall colors are a delight. There are upright and graceful
weeping forms available. Some forms also have colorful winged seeds that
provide color interest in the summer. Be
sure to look for heat tolerant cultivars.
Flowering Crabapple (mature height
10' to 25', depending on cultivar) - with over 200 cultivars there are many
different types available - from those with white to pink to red single or
double flowers; with tiny 1/4" fruit to larger 1 ½ “ crabapples; with
yellow or red fruit; and from upright to columnar to mounded to weeping forms.
Several of cultivars also add some fall color to their list of
attributes. Look for varieties
resistant to mildew and fireblight. In
this area it’s best to select cultivars with very small fruit so you won’t
be required to apply regular pesticide sprays to control the codling moth.
Flowering Cherry (mature height 12'
to 50', depending on cultivar) - perhaps one of the most beautiful small
flowering trees available. Like
the crabapple you’ll find a variety of flower forms from white to pink;
large or small; single or double. The
tree form varies with upright, spreading, and weeping forms available. Many
cultivars have a bronze to deep red fall color.
Borers can be a problem, especially if the tree is stressed, and is
also subject to several fungus diseases that attack trunks, leaves and twigs.
Consider a flowering cherry a short-lived (20 years) tree.
Paperbark Maple (mature height 25') -
this is an interesting little maple with dark green, tri-foliate leaves that
turn a brilliant red in the fall. The
exquisite reddish bark peels off in thin sheets.
The form is upright oval to round.
This is a wonderful small maple, especially in the fall and winter
landscape.
Redbud (mature height 20' - 25') -
here’s a tree that everyone falls in love with when they see it in
springtime bloom, especially those cultivars with deep, purple-rose flowers.
Flowers come out before the leaves in early spring and adorn the bare
branches. The tree usually branches close to the ground and develops a
spreading, somewhat flat-topped crown. Look
for heat resistant varieties like `Oklahoma’ with glossy leaves and red
tipped new growth.
Amur Maple (mature height 5' to 25'
depending on the cultivar) is another small maple that should be considered
for its magnificent orange-red fall color. This tree is a low branched,
multi-stemmed tree with a variable shape. It’s very winter hardy and can be
utilized in above-ground tree planters. For dependable fall color select a
cultivated variety, such as `Flame’ or ‘Red Rhapsody.’
Dwarfs or Giants
In the nursery trade there are some
cultivars of larger trees that meet the size criteria of a “small” tree.
While they may not have quite the pizzazz of these other smaller flowering
trees, they can still be utilized in the landscape where a smaller tree is
needed.
Leprechaun™ Ash is a dwarf form
with a mature height of 18' of the green ash.
Golden Desert Ash™ (mature
height 20') is a cultivated variety of the common or European ash with
yellow-green leaves and bright golden twigs.
Red Cascade™
or Dwarfcrown is a compact (mature height 16', mature spread 8')
cultivated variety of mountain ash with an oval shape. It has white spring
flowers, yellow-orange fall foliage, and orange-red berries for multi-seasonal
interest. `Longwood Sunset’ is another smaller mountain ash with orange
berries
Globe Norway Maple (mature height
15') is a “lollipop” tree with a dense rounded head that is much shorter
than other Norway maples. A very
formal looking tree.
Harder to Find and Not Well Tested for This Area . . . But Worth a Try
Serviceberry (mature height 15' to
20') might be called a shrubby, multi-stemmed tree or a large shrub with early
spring white flowers and bright red fall color. Some cultivars also have
purplish blue berries. Plant in a more protected location where they’ll get
afternoon shade.