Pruning may sometimes consist in cutting back a jagged stump where a branch has been broken off. The stump should be cut close back to the bole, smoothly and cleanly, and then coated with gas tar. Dead branches should also be removed promptly.
The principal evergreens require very little pruning. Sometimes a little shaping may be needed, but there is no such thing as annual pruning, except for hedges. A weak plant may be cut back.
Berberises and Hollies only need shaping. At the same time they will endure pruning if formal growth is wanted; and this is best done at mid-spring, because then the new growth soon hides the stumps. Laurels often require severe repression and it should be done with the knife in April. ivy should also be clipped then.
With respect to deciduous trees, the smaller flowering trees may be shortened when young to get an open framework of branches, but afterwards they will require no pruning, unless it be to thin a much-crowded head or trim in a straggling branch. A strong leading growth is not wanted. The larger shade and shelter trees should have a clean main stem extending upwards as a leading growth, with side branches breaking from it. As a rule, it is not well to shorten the head, as advised for the small flowering trees, because a spreading, cabbage-like head is not wanted.
Conifers rarely require any pruning. A continuous main stem or "leader" is necessary. If a tree forks into two leaders one should be removed.
The following tables will serve as a guide to pruners:
(Pruning consists in cutting the flowered shoots of the previous year close back in winter or when growth starts in spring).
Buddleia variabilis and Veitchiana.
Ceanothus garden varieties and hybrids such as Gloire de Versailles.
Clematis Jackmanii and its forms.
Roses (dwarf, hybrid).
(Most of these are spring bloomers, and the pruning out of the shoots which have flowered should be done in early summer, so as to give the new wood which is springing up a chance of developing freely and ripening well; but the summer and autumn bloomers, such as the Rambler and Wichuraiana Roses and some of the Spiraeas, cannot be pruned till late summer or early autumn. The new shoots will bloom the following year.)
Fig. Pruning Shrubs - A framework showing the old wood, the wood of the previous year, and the shoots of the current year.
Fig. Pruning Shrubs - How to prune shrubs which flower on new wood. - (1) main stem of a Clematis Jackmanii trained on an arch; (2) points where all the young wood (3) of the previous year is cut back in spring.
Fig. Pruning Shrubs - How to prune shrubs of the Raspberry and Rambler Rose habit. - (1) old dark shoots to be cut out at the base in summer; (2) young shoots to be retained for next year's flowering; (3) an old shoot shortened to allow the retention of a young shoot growing from it.
Fig. Pruning Shrubs - How to prune shrubs which bloom from the old wood. - (1) a Wistaria planted against a wall; (2) side branches trained in tiers to cover the wall; (3) young shoots pruned close back in winter or early spring; (4) racemes of bloom springing from the mature wood.
Ribes (see also group 4).
Rose (Rambler and Wichuraiana)
Sophora (not japonica).
* The Dogwoods grown for their coloured stems in winter should be cut down every spring. Golden Elder the same. The beautiful purple-leaved Nut, Corylus maxima atropurpurea, should be cut down about every third year. Most of the Spiraeas respond well to cutting hard back annually, this being done in Winter or early Spring.
(Pruning consists in thinning when crowded and spurring back the young shoots to two or three inches in spring where numerous. Very little general pruning is needed.)
Prunus (see also Group 2).
(Some shrubs, in practice, require no annual pruning. The most that is likely to be needed is a little thinning and shaping every two or three years. The following come within this group):
Cercis (Judas Tree).
Cistus (Rock Rose).
Erica (Heath), remove old flower heads.
Genista (see also Group 1.).
Helianthemum (Sun Rose).
Honeysuckle, winter flowering.
Liriodendron (Tulip Tree).
Lonicera fragrantissima and L. Standishii.
Fig. The monarch of the terrace. A noble Weeping Willow. For description see Chapters 14. and 22. Photo by F. Mason Good.
Fig. Stone Pine (Pinus Pined) At Kew. For description see Chapter 27. Photo by R. A. Malby.
Ononis (see also Group 1.).
Vitis inconstans (Ampelopsis Veitchii.).
It should be understood that weakly plants of the above may be cut hard back with advantage. Crowded bushes may be thinned. Young plants may be shortened to induce new branches to break. But, broadly speaking, healthy, well developed plants need only occasional thinning.
Paulownia imperialis is sometimes used for subtropical purposes, and is cut down every spring to get fine leaves.
The variegated and golden Elders may also be cut back annually.
Lilacs are disbudded as described in Chapter 26. Basal suckers should be cut out.
The Thorns (Crataegus) when grown as standards may have the heads shortened once or twice while young, but no annual pruning will be needed.
The Winter Jasmine may be pruned severely after flowering, and strong growths will push which will bloom the following winter.
In pruning trees, due weight must be given to the consideration of getting a good bole. In nature trees are crowded, and this tends to the production of fine stems, because the trees draw up to the light and the lower side branches gradually shrink away. But the bole may be "feathered" with small branchlets.
In park planting, or any planting for distant group effect, particularly with Firs and Pines, the trees may be set close with this object in view. On a lawn or other sites near a house single planting is better. Most of the Conifers are wanted well feathered with foliage to the ground, and if uncrowded, and kept to one leader, they will be well shaped. As regards the larger deciduous trees, the desiderata are a clean bole and a large spreading head. These features may not come without assistance from the pruner in the early stages. The lower branches should be kept shortened for the first few years, but should be allowed to carry some leaves, as the foliage helps to thicken the stem. Later the lower branches can be removed altogether. There should only be one leading shoot.