Pruning to control disease
Appropriate pruning can also be a positive means of controlling disease. With canker, for instance, you may be able to cut out affected branches entirely or pare off diseased tissue until clean wood is reached; then paint over with a proprietary anti-canker paint.
Die-back is a serious peach and nectarine trouble which will cause the death of shoots, starting from their tips. Often first noticed in spring when expected renewed growth does not occur, the uninitiated may put this down to frost damage. Pruning in late spring, after growth has begun, ensures that all dead wood is removed. The infection can be detected before a whole shoot is killed— look for a brawn stain spreading from the centre of the shoot. Cut back until the cuts show clean white wood within.
Powdery mildew can be a menace to the apple grower. Here it is possible for the experienced and watchful primer to detect infected shoots by their lighter colouring. Cut such shoots out and put them on the bonfire at once. Where infection has distorted terminal shoots it is prudent to take off in winter at least an inch or two from every one-year-old shoot.
In the course of winter pruning one can also look out for dead spurs and shoots killed by the brown rot fungus and the lesions in the twigs of apples and pears, arising from scab fungus infection.
In pruning away dead and diseased wood, the blade of your knife, secateurs or saw may carry infection from one part of a tree to another, or to another tree. To prevent this possibility dip the secateur or knife blade into a 3”, solution of lysol or swab the saw thoroughly with the disinfectant immediately after dealing with any diseased part.
Tools and techniques
For cutting all the smaller growths a pruning knife or pair of secateurs may be used. On the whole secateurs are safer than a knife and the home gardener will find the modern implement can do an excellent job. Keep the blades sharp and use the secateurs decisively. If you have any trees much taller than yourself, a pair of long-handled pruners will prove a great convenience. The older gardener will also find them helpful as they enable low-growing subjects to be cut with less stooping.
On smaller shoots the cut should be made close to a bud on the branch-end side of it, slanting slightly behind it, but neither so close as to injure the bud or far enough away to leave a snag of wood which will later die and invite disease or infection.
Where primary or secondary branches have to be removed or shortened, cut where the branch joins another or emerges from the trunk. In this case a saw is necessary. An ordinary bow saw is excellent. For some work a pruning saw, which cuts when you pull instead of as you push, is helpful. For larger branches reduce the weight by making one or two preliminary cuts, working from the tip, and finally cut as nearly flush with the trunk or larger branch as possible. With these larger branches you should first make a shallow cut on the underside and then saw downwards from above to meet the first cut. This will prevent bark-tearing. Pare wounds clean and cover at once with a proprietary tree paint or real white lead paint.
Trees that trespass
You may find yourself required to prune a tree for reasons that have nothing to do with cultivation. Should one of your trees obscure the sunshine from your neighbour’s garden or spoil his view, he cannot demand that you prune, only ask you to do so. But if the branches of one of your trees, or its roots, enter your neighbour’s garden, the case is different: you are guilty of causing a nuisance, possibly of trespass. Here, if your neighbour complains and you take no action, he may do the job himself, cutting back the encroaching branches or roots, but both of these will still belong to you and he should give the prunings back.
Similarly, if the branch of a tree overhangs the public highway, the local authority can require you to remove it, and will take the necessary action if you do not.
Root pruning is a form of pruning aimed at restricting the sap flow to over-vigorous and unfruitful trees. Dig out a trench about 60 cm (2’) deep and 30 cm (1’) wide at between 60-150 cm (2-5’) from the trunk depending on the severity of pruning desired. The cut all the roots which cross the trench with secateurs or a sharp spade. Root pruning can be used as an alternative to bark-ringing when there is a possibility of disease entering through the wound produced when ringing.