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EASTERN WHITE CEDAR
(Thuja occidentalis)
Eastern white cedar (the name 'cedar' is a misnomer - true cedars
are native to Africa and Asia) is an evergreen native to the north-eastern
part of North America roughly bounded in the north by a line drawn
from the southern tip of Hudson Bay west to the Ontario/Manitoba
border and east to Nova Scotia. In the south, it occurs along the
southern shores of the Great Lakes and most of the New England states.
The leaves are yellowish-green and scale-like. The fibrous bark
is reddish brown and peels off in narrow strips. Both wood and foliage
are highly aromatic. The wood of Eastern white cedar is long lasting,
making the specie ideal for bonsai featuring deadwood.
When growing in the open, cedars are straight-trunked with a slightly
conical, columnar crown which extends to the ground. The foliage
is dense, and the tree has an almost pruned appearance. The root
system is shallow and wide-spreading, making the trees adapt easily
to life in a bonsai pot.
In areas where they are subjected to abuse by wildlife and the
elements, cedars attain the trunk shapes that make them ideal bonsai
subjects. Because of poor soil conditions and periods of extended
drought during the growing seasons, cedars growing under those conditions
are naturally dwarfed, and can frequently be found with shari and
jin in place, although requiring some refinement. Cedars are suitable
for all bonsai styles.
Foliage:
If cedars have a drawback, it must be their foliage. It is similar
to the foliage of Hinoki cypress but not as tight. On the other
hand, it is not as curly. Fronds will grow every which way, and
the view of regular cedar foliage can be daunting for the bonsai
novice. However, with judicious pruning and pinching it can be forced
to behave and form foliage pads not unlike those of junipers.
Cedars grow throughout the growing season without a period of rest
if conditions are appropriate, which they should be if they are
being grown as bonsai. They therefore need to be pruned and pinched
frequently. If you time your pruning sessions to coincide with the
appearance of Haley's Comet, your cedars will not look good. Each
of my trees is subjected to at least two scissors pruning sessions
per growing season in addition to being pinched whenever something
sticks up down or out. Unless this pruning is carried out religiously,
cedars will develop elongation shoots with long internodes.
While I have seen cedars bud back on 300-year-old trunks in the
bush, I have never had that happen on the trees I grow as bonsai.
There must be special ingredients in the air 'up north'. Anyway,
they do bud back on younger twigs, and also on areas of the trunk
where branches are or have been growing
As all trees, cedars shed old foliage in fall. Some time in September,
part of the foliage, usually in the interior of the tree, will turn
rusty brown and slowly fall off. If you're not sure whether your
tree is shedding or dying, pulling at the brown foliage is a reliable
test, because the foliage about to be shed comes off easily, while
the foliage about to die requires a lot of force to come off. I
believe to have noticed that this natural shedding can be reduced
by timing one of the heavy pruning sessions to occur around the
middle of August.
Fertilizing:
Cedars like lots of fertilizer, and I feed mine bi-weekly with a
full strength 30-10-10 chemical fertilizer beginning about the end
of May and ending the middle of August, and another couple of applications
in late September and early October. I alternate between different
products, including Miracid. Such fertilizing gives the trees dark
green foliage and lots of growth, which, of course, is mostly pruned
off, but does contribute to the denseness of the foliage pads. I
start with the fertilizing regimen in the year following collecting.
Pests:
Cedars are relatively free of pests. The only ones I have ever encountered
are scale and leaf miner, both controlled by spraying with a systemic
insecticide. A cedar suffering from a leaf miner infestation is
not a pretty sight, and ever since almost my whole collection of
cedars was attacked by these insects in 1994, I give them two precautionary
applications of a systemic insecticide - one in early May and another
about two or three weeks later.
I spent much of the spring of 1995 plucking all the dead foliage
off the trees, but I am happy to be able to report that they all
survived.
Winter care:
As you would expect from a tree that is native to this region of
the American continent, cedars are very winter hardy. If you have
marveled at the pictures of growers in some parts of Japan leaving
bonsai on their benches all year round, marvel no more, because
that is what I have been doing with some of my cedars. Why not all?
Well, better safe than sorry, so while it is true that I have left
cedars sitting on the bench all winter long, I do use some judgment,
mainly relating to the size of the root ball. But putting the trees
on the ground in a shady spot is quite adequate to ensure their
survival in the Toronto area.
Cedar foliage, like that of some junipers, changes colour in winter,
becoming grayish-green with maroon undertones. This also can be
startling to those not familiar with the tree's habits, but checking
the underside of the foliage should still reveal a healthy light
green shade and signal that all is well. The winter colour disappears
within a few days in spring.
Wiring:
Cedars are very particular when it comes to wiring the young fronds.
There is no problems wiring branches, other than that old ones are
very stiff and somewhat brittle. When wiring the foliage fronds,
care has to be taken not to change the growing angle too drastically.
As I hope the accompanying pictures show, Eastern white cedars
can make good bonsai. Because of their foliage and trunk characteristics,
they are best suited for larger trees - good specimens smaller than
12" or 15" are difficult to find and even more difficult
to make into convincing bonsai. If you live in an area where cedars
are native, it is well worth looking for spots where they are naturally
dwarfed - usually associated with poor soils - and get permission
to dig up a few. When you do, keep them in the shade for about a
month afterwards and spray the foliage frequently (four or five
times a day, if you can) with water through a fogging nozzle. In
the second year, start fertilizing heavily and do some initial pruning
as required.
More information is available at:
http://www.rook.org/earl/bwca/nature/trees/thujaocc.html
http://www.canr.uconn.edu/plsci/mbrand/t/thuocc/thuocc1.html
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