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The
yew tree has become one of my favourite species of bonsai to
work upon; this is mainly due to the ease of styling and the
dramatic contrast between the lush green of the foliage and the
beautiful reddish bark that they purvey.
The two main species
of yew commonly used for bonsai are:
TAXUS 'baccata' "English Yew" green leaves lighter in colour to
its Japanese counterpart.
TAXUS 'cuspidata' "Japanese Yew" dark green leaves with light green
undersides.
Both trees can bare
fruit with a red aril.
There
are also many cultivars off these two main species, such as the
variegated variety TAXUS baccatta 'Fastigiata Aureomarginata'
the goldern Irish yew, that can be very hard to create into bonsai,
because of its upward pointing branches you will need to wire
down constantly and the yellowish rim to the leaves gives a sickly
chloritic appearence to the design.
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N.B; As
many of you will know the Yew family is poisonous so take care
with children etc when pruning.
One of the biggest
considerations when it comes to pruning Yew trees is their apical
dominanace, you should basically regulate this by pruning strongly
around the top to prevent the top branches swelling out of proportion
to the trunk and by making the energy go to the basal branches
which will intern promote more swelling around the base of the
trunk, this can obviously be sped up by growing sacrifical branches
as well. The species will also bud readily on old wood around existing
nodes when vigorous and healthy, which can be very benefical when
working upon old collected trees. Due to this readiness in budding
they are very forgiving to poor pruning, but I will try to explain
the correct pruning regimes to stop die back and daage to the tree.
PINCHING
In the spring
time the trees buds will burst into life producing light green
shoots of growth, which should be allowed to extend to about 3-4
cm before pinching, this task is done by using the finger and thumb
(not the nail) by supporting with one hand the base of the new
shoot while plucking in half with the other. Now if the desired
length of the pad has already been achieved it is possible to completely
remove the new growth tip shoots to make the tree back bud in the
inner of the foliage pad providing the tree is healthy. This procedure
can be carried out as the tree puts on its growth extensions, but
if you leave the growth over a period without pinching the shoots
will harden off and become impossible to pinch, so you will have
to prune with scissors.
PRUNING
As this tree
is so vigorous, when structuring your pad you will need to remove
opposing side shoots usually the growth extensions on the inside
of the branch curves.
While the tree
is in full active growth (May- Beginning of August) it is possible
to prune back with sharp scissors anywhere along the foliage shoot
providing you leave some foliage as a sap drawer after you’ve
pruned. To minimalise damage to the leaves you should cut at a
45° angle to the shoot with scissors so you can prune between
the foliage.
Autumn and Winter
pruning is possible on this species, but you must cut back to a
secondary back shoot, so the energy going up the stem will just
be diverted into another growth tip. During the summer period it
is advisable to thin out the dense canopy of refined specimen trees
to allow light into the basal branches, you should do this by plucking
the leaves off around the junctions within branch structure and
removing downward pointing leaves within the foliage pads.
WIRING
The
yew tree can become very dense through its vigorous growth habit,
so a lot of the problem with wiring the tree is applying the wire
to the branch without going over the leaves. To prevent this problem
it is possible to pluck some of the inner leaves where you do not
wish the tree to produce buds, leaving foliage at the tips. If
you wish the tree to back bud in areas that are still too dense
you can cut back the leaves close to the stem leaving the dormant
dud within the base of the leaf.
REPOTTING
Repotting should be done
just before active growth so this would vary greatly in Britain
according to our changeable weather. In the sunny south of England
where I am they usually come into growth around April depending
on where you are keeping the tree e.g. Greenhouse etc, so I usually
start around the beginning of April. The Yew tree has very fleshy
roots so you have to be a little gentle when teasing out the roots
with a root rake not to damage too much. I find a gentle hosing
of water can sometimes help get into very stagnant existing soil
mixes, especially with collected material. This species should not
be root pruned too hard because their Spring burst of growth will
not be able to sustain excessive root pruning, but remember to prune
to achieve a good radial root growth, for example leaving the weaker
area and only prune the dominant area of root. If you are repotting
out of doors you should be careful of drying winds affecting the
fleshy root ball, so you can stop this by misting regularly with
water until it is transplanted and watered in. The best soil mix
I have found for this species is 80% Sifted from dust and graded
3-4mm Akadama soil the hard double red line grade, 15% 3-4mm Cornish
grit to enhance drainage and to stop the Akadama clay from breaking
down and 5% Sphagnum moss cut up and sifted through a coarse sieve,
at the moment I have found the live New Zealand moss to be very
good that they sometimes sell for hanging baskets.
The Yew tree has very
fleshy roots so you will need to frost protect in the winter, but
a lot of the problem can occur from too much water retention within
the soil with poor draining cold soil mixes, so it will obviously
be more important to protect these trees until you can change the
soil medium.
Due to this species having a very fleshy root I have found the growth
habit to be not so good grown in a plastic bonsai pot, because the
trees root ball can not breath through the plastic wall lining.
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