Evergreen Arborist
TLC for Japanese Maples
The News Tribune, May 22, 2004
Japanese maples add beauty and class to many Puget Sound
area landscapes.
They represent one of my favorite trees to prune - even though I may look
strange crawling beneath a three-foot tall laceleaf to start the work.
However, professionals and "true blue" gardeners take the plunge
in order to do a proper pruning job.
Below are a few tips on how to enhance the beauty of your Japanese maples.
They apply to both the low growing and the upright varieties. Some of
the more common environmental and disease problems will also be discussed.
Pruning Tips
Some degree of tree pruning can be done most anytime. If
your maples were not pruned during the fall or winter, summer is a good
time to remove interior dead branches and to thin the crowns.
The first step is to put on some grubbies and protective eye gear. The
second step is to purchase good quality pruners and a small folding type
of saw. Now you are ready to assume the on-your-back position to begin
to beautify your Japanese maple. The secret to pruning the low growing
varieties is to work from the inside out until the tree's foliage is thin
enough so the intricate branch structure is visible.
The initial targets are dead twigs and branches on the interior of the
crown. This dead material is normal and usually snaps off easily using
your fingers. Larger dead branches should be cut or sawed off.
Next, trim out live branches and twigs that point in strange directions
that interrupt the natural outward "flow" of the foliage.
Then concentrate on thinning out small twigs and branches where they
are very numerous. Removing the deadwood and thinning live growth can
be done in one section at a time as you move about under the tree.
The most important rule is to cut a branch near a bud or where a branch
joins the trunk or a larger diameter branch. Try not to leave stubs because
they will die back and become entry points for decay.
Be careful not to over-thin. Removal of around a quarter of the live foliage
should be the goal, not counting the dead wood.
Common Problems
First, many maples are planted too close to buildings or
walkways. They look very innocent when young and small, so be aware of
how large a particular variety is expected to grow. Second, most varieties
do better in partial or full shade, so plant a tree where it will best
thrive.
Fortunately, few insects cause problems that are noticeable on Japanese
maples.
Environmental problems often cause some type of leaf scorch during the
summer. This may due to lack of moisture or exposure to sun during the
hot summer months. Usually the trees will recover the following year.
Japanese maples are generally disease free. However, they are very susceptible
to the soil borne fungus verticillium wilt. The signs are wilting leaves
followed by a twig or branch dying. When a branch is sliced into, greenish
or brownish streaks may be visible.
The fungus may progress throughout a tree or stop after a few branches
have died. There is no cure, but the dead material should be cut out.
If a tree dies, remove it and as much of the root system as possible.
Do not plant a maple back into the same area.
A Caution When Hiring Tree Trimmers
I have talked to homeowners that were chagrined at the results
of a pruning job - or should have been! Some tree pruners seem to feel
a tree should look like it has been really worked over. So be aware of
the "pruner" that is stalking your Japanese maple or other ornamental
trees with hedge trimmers or chain saw in hand.
Ask the individual or pruning crew to explain and to demonstrate what
it plans to do. Have a full and complete understanding of what you expect
the results to look like.
Even if you do not know how a tree should be pruned, still ask for an
explanation or demonstration. If you suspect a butcher job is a possibility,
then consider hiring someone else.
Taking the above precautions will decrease the chances of having to painfully
write a check after discovering that your favorite tree has been reduced
to stubs!