Probably one of the most difficult decisions to make with a garden is what to do about old fruit trees. They are going to remain large and dominate an area if left, yet are also a source of immediate production and a shame to remove. If they are in the way and have to go for good reasons then their crop can usually be replaced with another new tree planted elsewhere. But do not use the excuse that a tree is old and past renovating. Even if the trunk is hollow enough to hide in as long as there is no serious fungal infection or root damage then a tree may go on for years of generous cropping. With care most can be recovered into fine health and production, though some are less worth it.
Apples, pears, quinces, mulberries and nuts seem to live for ever and can usually be made over anew. Plums and cherries get more difficult and apricots likewise. These stone fruits can be tidied and fed but once they start to go they are hard to rebuild -especially as they must be pruned in summer and they resent it. Peaches are very short lived rarely being productive after a few decades and seldom worth the effort -particularly as newly planted ones crop heavily and quickly.
And just because they are big does not mean trees are centuries old, most are much less. Apples and pears may just make a century or more and generally outlive the stone fruits with the peaches, cherries and apricots expiring before the plums. Most stone fruits are prone to fungal silver leaf infection and have brittle wood; not recipes for longevity.
The biggest apple tree in your old orchard may not be the oldest but I’ll bet you it’s a Bramley; this variety always gets huge. Most old trees are big. Well trees now coming up for renovation can hardly be on modern very dwarfing stocks but on older sorts which were not always so dwarfing, though they certainly have proved long lived. Thus most old trees have got much bigger than ever will the ones we are now planting. Even trees that were once trained as cordons and espaliers and so on are likely to be on much stronger stocks than would be chosen now. However those trees would also have been pruned harder and fed more than most of us now manage. Do not try to compress these down to a modern smaller copy but just rework them as they are.
Those more fortunate to be restoring trees planted in the last few decades that have gone unpruned may have a similar task but the scale will be much reduced as they will certainly be less vigorous and much dwarfer trees, or at least should be. (If they are getting very big see whether the scion has rooted bridging over the graft?)
Before doing any renovation it is a good idea to get the trees back into general good health. Get rid of any grass or other plants underneath and around the trees(especially for pears) and if it is compacted fork the soil to aerate it. Remove any redundant stakes and ties, fix new ones properly if they’re necessary. Remove any surrounding congestion such as over-grown hedges as good air flow and light are also essential for a healthy recovery. Water well and give an all purpose organic feed, preferably high in humus such as compost or muck. Plan so you can give a jolly good watering regularly for a whole growing season before and after any really major work.
Just feeding and watering are usually enough to restore most trees especially if they are also given seaweed sprays and waterings which provide trace elements. Old trees have suffered a continuous loss of minerals not just carried away in their fruits but in prunings which are very rich in potash. This loss affects all trees that have been cropped and pruned for decades but especially cooking apples which have an elevated need for potash. Thus the benefit of dressing around most fruit trees with ashes after a bonfire and particularly for cooking apples. Old stone fruits may also become very short on lime and though getting some lime from wood ashes would also enjoy a dressing of chalk or ground limestone.
At any time remove dead, and especially any decaying wood before it spreads. Also remove suckers as they are literally sapping your trees growth. Suckers need to be pulled off or cut out from as low down as possible. Ideally excavate around them to where they emerge and surgically remove them. Leaving any bit of a sucker soon leads to their regrowth and multiplication. I dress the wounds with wood ashes to deter rots and soil organisms but a tree pruning compound or paint would probably do better.
As mentioned above in some cases the graft may have been bypassed and the tree scion rooted directly itself thus obviating any effects the rootstock was supposed to have. The tree will often become vigorous and unfruitful. This often occurs after the passage of years as material becomes added to the soil and the base of a tree slowly submerges. This is difficult to deal with as leaving the extra roots from the scion may retain too much vigour while removing them may lead to the loss of the tree if the original rootstock is not very extensive. The best course is for the offending roots, or rather their connection, to be removed piecemeal over several years. On younger trees they may probably be removed more rapidly.
Another similar problem that can arise with old trees is the constant accumulation of soil burying the roots too far from the warmth and air. So although most trees enjoy a thick mulch for the moisture retention and cool root run this can be overdone. Trees with their roots deeply buried tend to do poorly and in olden times would have been dug up and replanted. Although achievable it is less effort to scrape some of the soil away instead, even as far as exposing the topmost roots. Even huge trees can be lifted, their roots pruned and then replanted but it is a big job. Certainly it is one of the best ways to make a strong unfruitful tree crop. Pruning the top growths may not be as effective but is more maneagable.
Trees left to themselves usually produce shed loads of fruits but these are small. They may also be such huge crops the trees take years off to recover. What we need to do is to reduce the number of fruits formed and have the majority of those on wood exposed to the sun and air. Although the best is always to leave well alone, if pruning is judged necessary then be bold with overgrown trees. We can usually cut up to a fifth or quarter of a tree away when dormant and it will spring back with vigour, more than that may check it permanently.
Ideally do remedial pruning when the leaves fall so you can see what you are doing. (Mark stone fruit trees with paint to indicate where you want to remove what and then leave it till next summer when it will be the right time to prune them. As these cannot be pruned when dormant they are usually treated more lightly with less removed in any one year.)
Use a clean sharp saw and clean sharp secateurs, both sterilized with methylated spirit between trees. Take sensible safety precautions and do not work on your own, especially on steps.
First tidy; remove dead, diseased, rubbing and damaged bits. Obviously anything girdling and strangling a limb or trunk must be detached- it’s surprising how long old labels and ties can last. (You can’t read the plant name on the label anymore but the nursery’s is still legible of course) Thinning may be necessary if not hard cutting back to let more air and light to the fruiting wood if it is very congested. Remove whole branches rather than a lot of little bits. Take more wood from the shady parts and leave more in the sunny. And do remove anything you catch your self on or pointing at eye level.
With trained forms such as cordons and espaliers after thinning the limbs to a decent framework the spurs may still number too many and be too long. Sticking out too far from the framework they break under heavy crops and if on a wall lose the benefit. These are normally heavily thinned in winter when the tree is dormant, however I have found it possible to thin them when they are in bloom. Then it is easier to tell the fecund spurs and enables more of the healthiest ones to be retained and the poorer to be more ruthlessly cut back.
If there are a lot of water sprouts, whippy vertical shoots, these should be removed. However it is better to remove these in a separate operation in summer when they are less likely to be replaced. They are often a sign of a recent increase in vigour, say from excessive feeding or very heavy winter pruning and so such trees should not be heavily winter pruned or fed.
An interesting point with some of the older varieties of apple is they are prone to rough knobbly excrescences, masses of incipient roots. The very earliest varieties were often propagated by baton or truncheon cuttings. Very large ‘cuttings’ like light fence posts were used of such varieties with their ready to go root system. I’ve not tried but it works for mulberries.
A tricky point is what to do about wounds. Some experts would have they are best left alone. I prefer to paint on Forsyth’s compound of cow dung and wood ash but most use commercial tree pruning compounds or paint. I reckon it must be better to cover wounds to keep out wasps, beetles and water than to leave the wood bare. Likewise some fill holes with cement or plaster then seal and paint them over so rot can’t get in. I use Forsyth’s again though it needs topping up every couple of years. The commercial compounds look neat but some debate as to whether they prevent the bark healing, Forsyth’s compound was said to stimulate the bark to regrow. Certainly I’ve found it no worse and seemingly better for repairing my trees over the years.
Forsyth was famous at the start of the nineteenth century for renovating the King’s orchards. Although he did indeed use his healing compound it was probably as much his pruning and fertilizing that did the trick. His compound is two parts; a paste made of cow dung, soft soap, urine, lime mortar and river sand which you paint on first and then dry off applying a powder of baked bones and wood ashes. It works remarkably well but is fiddly, unscientific and very very messy.