PRUNING FLOWERING TREES AND SHRUBS
The art of pruning properly is one that is acquired by considerable
practice and observation. The first is necessary that the actual work
may be well and cleanly done, and it is only by observing the manner and
times of flowering of the different trees and shrubs which go to
constitute a well-kept pleasure-ground that the proper time to prune can
be thoroughly understood. The manner of pruning varies considerably,
some pinning their faith to a slanting cut towards a bud; some
preferring a straight cut; while others again are content with simply
slashing off the useless wood in the quickest possible manner. The
former is the best method, as it does not present a surface for the
lodgment of water, an important point with those shrubs that are of a
pithy nature in the centre of the wood, as the presence of water will
quickly cause the stems to rot and render the plant unsightly, even if
it escapes serious injury. All stems that are an inch or more in
diameter should be tarred over to keep out the wet, which either rots
them directly or injures them indirectly by making a moist, congenial
home for the various fungoid diseases to which so many of our exotic
trees and shrubs are liable.
Many shrubs which have been in one place for some years, and which have
become stunted or poorly flowered, are often given a new lease of life
by a hard pruning in the winter, cutting away all the old wood entirely,
and shortening the remainder. With a good feeding at the same time, they
will throw up strong young shoots, full of vigour, which will bear fine
and well-coloured flowers. Of course, a season of blooming will be lost
by doing this, but it will be amply compensated for in after years by a
healthy plant in place of a decrepit and unsightly one. The list
appended includes practically every flowering tree and shrub _hardy_ in
this country, with the proper time of pruning it. Those not specified
flower on the old wood.
When shrubs that by nature flower freely and are rightly placed with
regard to soil and position refuse to bloom, root pruning will sometimes
effect an alteration.
[Illustration: _CEANOTHUS AZUREUS AT KEW._]
ABELIA.--This genus is barely hardy, and, in most localities, is usually
pruned sufficiently or too much by frost. A moderate thinning of the
shoots in spring is sufficient.
ACANTHOPANAX.--There are three species of this genus hardy in this
country, and of these _A. ricinifolium_ requires no pruning beyond the
cutting away of side-shoots to a single stem, as it attains the
dimensions of a tree in Japan, its native country. _A. sessiliflorum_
and _A. spinosum_ are low-growing shrubs, and require an occasional
thinning out, which is best done in late summer to allow the remainder
to thoroughly ripen before winter.
[Illustration: _CEANOTHUS AZUREUS, VAR. MARIE SIMON._]
ACTINIDIA.--A climbing genus, easily grown in warm, sheltered
localities. They require very little pruning, but should be watched in
spring when growth has commenced, or the twining shoots will get into a
tangled and unsightly mass. Any growth not required should be cut away
in winter.
AESCULUS (Horse-Chestnut).--The common representative of this requires
little or no pruning, but the other species are benefited by a thinning
out of misplaced and useless branches in late summer to allow light and
air to the centre of the tree. This is especially important to all the
Aesculus in a young state. _Aesculus parviflora_ should have a good
thinning if the branches or suckers become at all thick, cutting all
growths not required clean away from the base.
AKEBIA.--"_Akebia quinata_ has flowered here, on an east wall, profusely
for the last seventeen years, under the following pruning treatment:
Cover the space allotted with the strongest shoots, and when new growth
pushes from the eyes or spurs in the spring, do not regulate it, but
summer-prune away all superfluous growth before it gets entangled. It is
from 'spurs' that the flowers are produced, and the more these are kept
clear, the more matured they become, and flower correspondingly."--E. M.
in _The Garden_.
AMELANCHIER.--These should be pruned after the flowers are past, the
removal of badly-placed and weakly shoots being all that is required. If
the plants are becoming too large, they can be shortened back at the
same time.
AMORPHA.--If flowers are desired of _A. fruticosa_ it should be kept
thinned out, and not be cut back; but the flowers are not showy, and it
is usually kept cut down every winter for the sake of its foliage. _A.
canescens_ should be cut down each spring to within two or three eyes of
the old wood, as it flowers best on the young growth.
ANDROMEDA.--The only recognised species of this genus is _A. polifolia_,
which requires no pruning.
ARALIA.--These should be kept to a single stem until they have attained
a height of 6 to 8 feet, after which they may be allowed to branch, or
be still kept to a single stem, as may be desired.
ARBUTUS.--An evergreen genus which requires no pruning.
ARISTOLOCHIA.--A genus of climbers which succeed best if the shoots are
not allowed to become too thick. The weakest should be cut away in
winter.
ARTEMISIA.--This genus is best known by its common representative, the
Southernwood, but this and the other Artemisias should be cut down
annually in a young state. When older, an occasional thinning out of the
shoots in winter is sufficient.
BACCHARIS.--Of this, _B. halimifolia_ flowers on the young wood and
should be cut back annually, while _B. patagonica_ should not be pruned
at all.
BERBERIS.--Properly the Berberis requires no pruning, but the
stronger-growing species, such as _B. aristata_, _B. Lycium_, _B.
virescens_, _B. vulgaris_, &c., require an occasional thinning to keep
them within bounds.
BERCHEMIA.--A climbing genus which requires no pruning.
BRUCKENTHALIA.--A dwarf-growing Ericaceous genus, the seed-pods of which
should be removed as soon as the flowers are past, or the plants will be
seriously weakened.
BRYANTHUS.--This should be treated the same as the last, which it
somewhat resembles.
BUDDLEIA.--Of these, _B. variabilis_, _B. japonica_, and _B. intermedia_
flower on the young wood and require cutting back every winter to within
two or three eyes of the old wood; _B. globosa_ need not be pruned at
all, except in a young state to keep it bushy; and _B. paniculata_ only
requires thinning out if it becomes too thick, which is not a very
common occurrence.
CALLUNA (the Ling).--This and its numerous varieties should have the old
flowers cut off as soon as they are past, and any long or straggling
growth cut back at the same time.
CALOPHACA.--The solitary representative of this genus is rather inclined
to become straggly if growing at all freely. When this is the case, the
plant is benefited by the cutting back of the longer shoots in winter.
CALYCANTHUS.--These require an occasional thinning of the branches, and
any long shoots may be shortened with advantage.
CAMELLIA.--These, which should be grown outdoors much more than they
are, should be cut down if they get unhealthy or unshapely, which should
be done in April. Otherwise no pruning is required.
CARAGANA.--Cut away all the straggling or misplaced branches.
CARMICHAELIA.--Requires no pruning.
CASSANDRA.--See CALLUNA.
CASSINIA.--These are grown more for their foliage than for their
flowers, and should be cut down in the winter or early spring. This can
be done annually or biennially according to whether the plants are
growing strongly or not.
CASSIOPE.--See CALLUNA.
CATALPA.--This genus contains some of our handsomest flowering trees,
all of which require careful pruning after the flowers are past,
thinning out the weakly wood, and shortening any long branches.
CEANOTHUS.--Of these, _C. americanus_, _C. azureus_, _C. integerrimus_,
and the garden hybrids, such as "Gloire de Versailles," "Marie Simon,"
"Ceres," &c., flower on the young wood, and should be cut back in
spring, allowing only sufficient shoots to remain to form a
well-balanced plant, and shortening them back to within two or three
eyes of the old wood. The remaining species flower on the old wood, and
merely require a shortening back of the stronger shoots and a thinning
out of the weakly ones after the flowers are past.
CELASTRUS.--A climbing genus of strong and vigorous habit with showy
fruits. They only require sufficient pruning in winter to keep them
within bounds.
CERCIS.--Requires no pruning, except such as may be necessary to make
well-shaped plants, which should be done after flowering.
CHIMONANTHUS.--The shoots of this should be shortened back after
flowering, and if on a wall they should be spurred in.
CHIONANTHUS.--See CERCIS.
CHOISYA TERNATA.--This only needs thinning after the flowers are over
and old wood removed.
CISTUS.--Those which are hardy of this genus should be cut back each
spring while in a young state, but when they have attained a flowering
size no pruning is required. The cutting back of young plants induces a
bushy habit, and also keeps them from weakening themselves by blooming
and seeding.
CLEMATIS.--The garden forms of this genus are divided into two sections,
of which _C. Jackmani_, _C. lanuginosa_, _C. Viticella_, and _C.
aromatica (C. caerulea odorata)_ are the types of those which flower on
the young wood, and which require cutting back close to the old wood in
the winter; while _C. florida_, _C. patens_, and _C. montana_ are the
types of those which flower on the ripened wood of the previous year,
and merely require a thinning out of weakly or unnecessary growth. Of
species other than those mentioned above, _C. Flammula_, _C.
paniculata_, and _C. Vitalba_ flower on the young wood; and the
remaining species are either herbaceous or flower on the old wood.
CLERODENDRON TRICHOTOMUM.--Thin in spring.
CLETHRA.--These practically require no pruning, but long shoots may be
shortened and weakly ones cut away with advantage.
COLUTEA.--These make better plants and flower later if they are cut back
every winter. _C. istria_ (a rare species) should not be cut down if
flowers are desired.
CORNUS.--The strong-growing shrubby Cornus, such as _C. alba_, _C.
Amomum_, _C. Baileyi_, _C. pubescens_, and _C. stolonifera_ require an
annual thinning out, and those with brightly-coloured stems should be
cut down every spring for their effect during the following winter. The
remaining Cornus require little or no pruning.
COTONEASTER.--The large-growing species should be pruned in late summer,
but only sufficiently to keep them within bounds; _C. Simonsii_ requires
cutting down annually while young to make it bushy, and the
dwarf-growing kinds are best left alone.
CRATAEGUS.--Keep the heads well thinned out to allow light and air to
the centre of the tree. This should be done in late summer.
CYTISUS.--These require very little pruning, with the exception of _C.
nigricans_ and _C. capitatus_, which flower on the young wood, and
should be cut back annually. The other species and varieties make better
plants if they are cut down each year while in a small state, but they
should be left alone when they have attained flowering size.
DABOECIA (the Irish Heath).--Cut away all old flower stems in early
winter.
DAPHNE.--Requires no pruning.
DESMODIUM.--These flower on the young wood, and should be cut nearly to
the ground-line every spring.
DEUTZIA.--The old wood should be kept cut out of these, but no
shortening of young shoots should be attempted.
ELAEAGNUS.--These require an annual overhauling to keep them in good
condition. This should be done in late summer, when the plants should be
well thinned out, and all useless growth cut clean away.
ERICA.--See CALLUNA.
ESCALLONIA.--These are usually cut back by frost; but if they escape,
_E. rubra_ and _E. punctata_ should have their long growths shortened
back in spring, while the other hardy species need not be touched. _E.
macrantha_ simply needs thinning. All the smaller growths in the centre
should be removed. _E. philippiana_ does not like hard cutting back, but
the old stumps must be cut out to make room for flowering wood.
[Illustration: _PEARL BUSH (Exochorda grandiflora) SHOWING ITS NATURAL
BEAUTY._]
EXOCHORDA.--These usually require no pruning, but if the plants are
getting too large or unshapely, they should be cut back immediately
after flowering.
FATSIA (_Aralia Sieboldii_).--This is usually cut by frost, but it
stands a cutting back in spring, when new growth is soon made which will
flower late in the following autumn.
FOTHERGILLA.--Requires no pruning.
GARRYA ELLIPTICA.--This always flowers on the previous year's wood. Need
only be thinned to ripen the new growth.
GENISTA.--_G. tinctoria_ flowers on the young wood, and should be cut
back every spring. The other species of Genista should not be pruned,
except to keep them in shape.
HALESIA.--These are small trees or large shrubs, and should not be
shortened back, but are improved if the growths are kept thinned out,
which should be done after the flowers are past.
HALIMODENDRON.--Requires no pruning.
HAMAMELIS.--Thin out regularly, as they are very apt to get thick and
make weakly growths.
HEDYSARUM MULTIJUGUM.--This flowers on the young wood, and should be cut
back lightly each spring. The growths can also be pegged down to improve
the plant, which is apt to get straggling.
HELIANTHEMUM.--Cut away all dead flowers and seed-pods after blooming.
HIBISCUS.--Thin out in winter, but only shorten the longest shoots.
[Illustration: _HYDRANGEA PANICULATA GRANDIFLORA (unpruned plant)._]
HYDRANGEA.--These flower best on young wood, and should be cut down in
winter. _H. paniculata grandiflora_ should _always_ be cut back to
within two inches of the old wood.
[Illustration: _HYDRANGEA PANICULATA AND VAR. GRANDIFLORA._]
HYPERICUM.--These should be cut back fairly hard in early spring, as
they all flower on the young growth.
INDIGOFERA.--Cut down every spring, as they flower on the young wood.
ITEA.--Keep the growths thinned and cut away all old wood.
JAMESIA.--This should be treated as the preceding.
JASMINUM.--_J. fruticans_ and _J. humile_ are shrubs which should be
thinned regularly; and _J. nudiflorum_ and _J. officinale_ are climbers,
which should be spurred in after flowering.
KALMIA.--Remove seed-pods as soon as the flowers are past.
KERRIA.--Cut away the old wood to encourage the young growths, which
yield the best flowers.
LABURNUM.--These should be thinned after flowering, cutting away the old
or weakly wood, and shortening any long or straggling shoots.
LAVANDULA.--Cut away all flower-spikes after they are past.
LEDUM.--Remove seed-pods after flowering.
LESPEDEZA.--See DESMODIUM, which it much resembles.
LEUCOTHOE.--_L. axillaris_ and _L. Catesbaei_ flower much better if the
old growths are removed and strong young shoots encouraged. The rest of
the genus require no pruning.
LEYCESTERIA.--Thin out old growths every spring.
LIGUSTRUM.--_L. ovalifolium_ and its golden variety are all the better
for being cut down each winter while in a young state. The remainder
merely require an occasional thinning.
LIRIODENDRON.--Requires no pruning.
LONICERA.--The shrubby Loniceras are nearly all inclined to become very
thick and full of weakly shoots if not well looked after. A thinning out
should take place after flowering is past. The climbing Honeysuckles
should only be pruned sufficiently to keep them within bounds.
LYCIUM.--These should be served the same as the shrubby Loniceras, but
the operation should be performed in autumn or winter, as they flower
practically all the summer.
LYONIA.--Requires no pruning.
MAGNOLIA.--Generally speaking, the Magnolias should not be pruned, but
cut away useless or decaying wood. Every wound, however small, on a
Magnolia should be tarred over immediately.
MICROGLOSSA.--The solitary shrubby representative of this is _M.
albescens_, which should be cut down in winter, as it flowers best on
the young wood.
MYRICA.--An occasional thinning is sufficient for this genus.
MYRICARIA.--Flowering on the young wood; this should be cut back every
spring.
NEILLIA.--Thin out every year after flowering is past, cutting back the
old wood to strong young shoots.
NEVIUSIA.--This requires the same pruning as Neillia.
NOTOSPARTIUM.--Requires no pruning.
NUTTALLIA.--The single species of this flowers in February, and is
improved by a good thinning out of the old wood when blooming is past.
OLEARIA.--Requires no pruning.
ONONIS.--_O. rotundifolia_ should be cut down every winter, as it
flowers on the young wood. The remaining species flower on the older
wood, and need not be touched.
OSMANTHUS.--These should not be pruned unless a particular shape is
desired, when the plants may be clipped with a pair of shears in spring.
OXYCOCCUS.--This is a small creeping genus allied to Vaccinium, and
requires no pruning.
OXYDENDRON.--Remove seed-pods.
PALIURUS.--This attains the dimensions of a small tree, and should be
kept trimmed up for that purpose.
PARROTIA.--Thin out in spring after the flowers are past.
PAULOWNIA.--Keep to a single stem to a height of about 8 feet, and then
allow it to branch. If used for sub-tropical bedding, it should be cut
down to the ground every winter.
PERAPHYLLUM.--The solitary hardy species of this should not be pruned or
disturbed in any way if it can be avoided.
PERIPLOCA.--A climbing genus which should be thinned out in winter, and
only shortened back if necessary.
PERNETTYA.--These should not be pruned at any time.
PHILADELPHUS.--These should be thinned after flowering, and the old wood
cut back to strong young shoots. This is especially important with _P.
microphyllus_, _P. coronarius_, and _P. Lemoinei_ and its varieties.
PHILLYRAEA DECORA (_Vilmoriniana_).--This well-known shrub needs no
pruning.
PHOTINIA.--Requires no pruning.
PIERIS.--Remove seed-pods.
POTENTILLA.--Thin out after flowering, and shorten any old wood back to
strong young breaks.
PRUNUS.--When young, all the members of this genus that are grafted or
budded are improved by being cut back each spring until they have
attained a fair size and shape. More especially is this the case with
the Almonds, double-flowered Peaches, and the various flowering
Cherries. When older, they need only be thinned and the flowering Plums
and Cherries kept spurred in, but not too hard. _Prunus japonica_, _P.
nana_, and _P. triloba_ should be cut down to strong young breaks after
flowering, the resulting wood bearing better flowers than the old wood.
If any of these three latter are grown on a wall they should be spurred
back hard after blooming.
PTELEA.--When young, trim these to form small trees, and do not allow
them to develop into ungainly bushes. When older, they require an
occasional thinning. _P. trifoliata var. aurea_, a golden form which is
not grown so much as it deserves to be, should be cut back annually or
biennially, the young wood being better coloured and bearing larger
leaves than the old.
PYRUS.--The wild Pears should be spurred in the same manner as adopted
for fruiting Pears, though not quite so hard. The wild Crab-apples, such
as _P. baccata_, _P. floribunda_, _P. spectabilis_, &c., should be cut
back every spring until they have formed well-balanced heads. Afterwards
an annual thinning and a shortening of the longest shoots after
flowering is sufficient. The remaining sections of Pyrus merely require
an occasional thinning. _P. japonica_ should be kept spurred in, whether
growing on a wall or in the open, and in the latter case should not be
allowed to become a mass of weakly shoots.
RHAMNUS.--These should be thinned out if becoming too thick, but, as a
rule, they require very little pruning.
RHODODENDRON (including AZALEA).--Remove all seed-pods immediately the
flowers are over, and any plants that are in a sickly condition should
be cut down at the same time. By doing this a season or two of flower is
lost, but it is practically the only means of bringing a weakly plant
back to health again.
RHODOTYPUS.--Cut away old wood, and encourage the strongest of the young
growths.
RHUS.--Keep these well thinned out, and destroy all suckers that appear,
unless wanted for stocks. Gloves should always be worn when handling any
of the Rhus, as the sap of _all_ is poisonous to a certain extent. _R.
Toxicodendron_ is _very poisonous_. This should never be forgotten. If
used for sub-tropical gardens cut down to within two eyes of the base.
Select the strongest eye and rub the other off. Always use gloves in
handling this shrub. It should never be planted where children have
access to it.
RIBES.--All the Ribes are improved by being cut down annually while in a
young state, but when older, a yearly thinning out of the old wood is
sufficient.
ROBINIA.--This is a genus that requires very little pruning when the
members of it have attained a fair size, an occasional thinning being
all that is necessary. In a young state they require well staking, and
the longest shoots should be shortened back, as many of them are
top-heavy when young.
ROSA.--Although the various garden Roses come under this heading, yet
they are a class apart, and are better dealt with by specialists. The
species of Rosa do not require any shortening of their shoots, which
should always be left at full length, but all of them should have an
annual thinning out of the old wood, either cutting it right away or
back to a young shoot. Some of the species are very prone to throw up
suckers from underground sometimes to a considerable distance from the
plant, and these should always be dug out and got rid of; merely cutting
them off only producing two evils in the place of one.
RUBUS.--This genus includes the Blackberry and Raspberry, and in a
modified form the treatment accorded to them for fruiting is the best to
employ with the ornamental Rubi, that is, all old wood that has flowered
should be cut away and strong young canes encouraged. But while in the
cultivation of the Raspberry only a few young canes are allowed to grow,
in the ornamental species practically every young growth should be
utilised. The double-flowered Rubi should have some of the old wood
left, as they do not make so much young growth as the single ones do.
SANTOLINA.--This is a dwarf-growing genus, the old flower-heads of which
should be cut away as soon as they are past, and any long or straggling
growths cut back at the same time.
SAMBUCUS.--The elders require very little pruning as a rule, but the
various cut-leaved, golden, or variegated forms are improved by being
cut back annually. This will prevent them flowering, but as good foliage
is required the loss of the bloom is a matter of little consequence.
SKIMMIA.--Requires no pruning.
SMILAX.--The hardy species of this genus do not require any pruning if
they have room to ramble. If space is restricted, thin out and shorten
in autumn.
SOPHORA.--These should be kept thinned when they have attained flowering
size; in a young state they should be kept to a single stem and induced
to form well-shaped trees.
SPARTIUM.--This should be cut back in a small state, but when older it
requires no pruning whatever.
SPIRAEA.--Though all the Spiraeas will flower on the old wood, the
following are better for being cut back in winter to form young
flowering shoots, viz., _S. betulifolia_, _S. Douglasi_, _S. Foxii_, _S.
japonica_, _S. Margaritae_, _S. salicifolia_, _S. semperflorens_, _S.
tomentosa_, and many of their varieties and hybrids. The remaining
Spiraeas should be kept thinned out, and if any are making strong young
breaks from the lower part of the plant they can be cut back to them
after flowering.
STACHYURUS.--This should be thinned out after flowering.
STAPHYLEA.--_S. pinnata_ should be kept thinned in late summer; _S.
colchica_ and _S. Coulombieri_ require very little pruning, but if too
tall or unshapely should be cut back immediately after flowering.
STUARTIA } Require no pruning.
STYRAX }
SUAEDA.--Cut back occasionally to keep it from getting ragged.
SYMPHORICARPUS.--Keep these well thinned out, which should be done in
late summer.
SYRINGA (Lilac).--these should be kept free of suckers, especially the
finer-named kinds, which are usually worked on stocks of the Common
Lilac. In addition, disbudding may be practised with advantage in the
spring, removing the majority of the blind shoots and any flowering or
leading shoots that are misplaced or not required. This should be done
twice or thrice at intervals of ten days or a fortnight.
TAMARIX.--Cut back in a young state, but when older they should not be
pruned at all.
VACCINIUM.--The removal of any old or rough wood is sufficient for
these.
VIBURNUM.--All the Viburnums grow thickly, and require an annual
thinning.
VITIS.--The methods practised in growing Vines for fruit suit the
ornamental species as well. If space is restricted they should be grown
on the spur system, and if there is plenty of room then the extension
system may be employed.
WISTARIA.--These should be kept spurred in, with the exception of the
leading shoots, which merely require a shortening in early spring
according to the strength of the plant.
XANTHOCERAS.--Requires no pruning.
ZENOBIA.--These require no pruning as a rule, but occasionally a hard
cutting back will induce healthy growth in place of a weakly one.
THINNING.--It will be gathered from these notes that thinning out only
is needful in many cases. If judicious thinning were more practised
English gardens would be more beautiful. It promotes internal growth and
a wealth of flowers.
Pruning is frequently carelessly and ignorantly done, and this applies
especially to forest trees. There are certain tools that may be used for
the purpose. Under ordinary circumstances only a few are necessary, and
these should always be of the best quality, sharp, clean, and always
kept ready for use. Take the pruning knife for example. If this is not
sharp it is impossible to make the necessary _clean_ cut. The surface
will be jagged and rough, and probably promote disease. Some prefer
_secateurs_, and while admitting their value for pruning purposes, a
good sharp knife is preferable; it is not so heavy, and does not tire
the hand. There are several of these implements in the market, but the
best that has come under my notice is the "improved double cutting"; it
is easy to work and cuts clean. For standard trees use the "Standard
Tree Pruner."