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 j.a.ponica_, _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. j.a.ponica_ 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 ma.s.s 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 cla.s.s 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 p.r.o.ne 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 s.p.a.ce 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.

j.a.ponica_, _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 s.p.a.ce 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.

ZEn.o.bIA.--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 circ.u.mstances 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."

CHAPTER VII

PROPAGATION OF HARDY TREES AND SHRUBS