PLEACHED OR GREEN ALLEYS
In the old days the pleached alley was as familiar in English gardens as
the pergola of the present age. Both are interesting, and both provide
grateful shadowed walks in the heat of summer. The trees most generally
used in the fashioning of pleached alleys were the Hornbeam and Lime,
both native of this country, but green alleys have been made of Yew, of
_Cotoneaster buxifolia_, of Holly, and other evergreens. There are
flowering Cherries of weeping habit that would suit well for such
treatment, and several other small trees of pendulous growth, such as
Laburnum, Weeping Ash, and the large-leaved Weeping Elm. There is an
important green alley at West Dean, near Chichester, of Laburnum only.
[Illustration: _A NUT WALK._]
The green alley differs from the pergola in that the pergola has solid
and permanent supports, its original purpose, in addition to the giving
of shade, being to support vines. The green alley, being made of stiffer
and more woody growths, only needs a temporary framework to which to
train the trees till they have filled the space and formed the shape.
Hornbeam was the tree most used in former ages, and for a simple green
alley nothing is better. Beech is also good. Several other of the
smaller trees of weeping growth should be more used for this and the
allied uses of training for arbours and other shelter-places in the
garden.
The common Plane is much used on the continent for green shelters; the
trees are pollarded at about eight feet high, and the vigorous young
growths trained down horizontally to a slight framework.
It would be interesting to make a green alley with two or perhaps three
kinds of plants whose leaf form was of the same structure. For instance,
a groundwork of Weeping Ash could soon be trained into shape, and
Wistaria would be best to grow all over and through it. The more stiff
and woody Ash would supply the eventual solid framework, as by the time
the Wistaria was making strong growth (for it is very slow to make a
beginning) the whole would be well in shape, and might dispense with the
framing of "carpenters' work" that is necessary for its first shaping.
It would be best to plant the Ash zigzag across the path so that the
main of the head of each tree might be trained across the path and down
to the ground on the opposite side, when it would occupy the space
between the two opposite trees.
It is important to further maintain the distinction between green alley
and pergola by using in the green alley only things of a permanent and
woody character; no Roses or Clematis, or any other plants of which
portions are apt to die or wear out. These are proper to the pergola,
whose permanent substructure makes it easier to cut away and renew those
of its coverings, whether structural or growing, that are liable to
partial decay.
A great many delightful things may be done with these green alleys and
green shelters. Much interest is already aroused in the pergola, and
when thinking of this it is well to consider these other ways of adding
to the comfort and charm of our gardens. One thing, however, should be
carefully considered. It should be remembered that where a path is made
more important by passing under trained green growths it should have
some definite reason for being so accentuated, certainly at one and
desirably at both ends. It often occurs that in laying out ground the
owner wishes to have a pergola, as it were, in the air, and when there
is nothing to justify its presence. It should not be put at haphazard
over any part of the garden walk. If of any length, it should distinctly
lead from somewhere to somewhere of importance in the garden design, and
should, at least at one end, finish in some distinct full-stop, such as
a well-designed summer-house or tea-house.
Another important matter is that a pergola or green alley, in the usual
sense, should never wind or go uphill. It is not intended by this that
shading coverings cannot be used in such places, but that they would
want especial design, and it is altogether a matter of doubt if these
could not be much better treated in other ways.
The circumstances of different gardens are so infinitely various that it
is impossible to lay down hard rules; only general rules can be given
and exceptional circumstances dealt with by exceptional treatment.
Green alleys require some attention. In winter the oldest of the wood
must be cut out to make room for the young growth, and when this is
lengthening vigorously it must be carefully laid in.
If the alley has an iron framework, which is necessary when such strong
growing things as Wistaria are used, this may be clothed during the
first few years, until the Wistaria is growing strongly, with annual
climbers such as _Cobaea scandens_, _lophospermum_, _Mina lobata_, and
even varieties of the large-flowered Clematis, which must be removed
when the Wistaria covers the alley.
[Illustration: _OLD APPLE WALK (Helmingham Hall)._]
Very charming alleys are sometimes formed of fruit trees--Pear, Apple,
Cherry, and Plum making delightful spring pictures, and almost as much
so when in fruit in autumn. Where fruit and flower are desired every
shoot must be exposed to sun and air. When densely shaded by other
growths the wood does not ripen, and therefore flowers badly, if at
all.