A tree improves with age
This is of course contrary to current thinking, particularly in commercial fruit growing. What I mean is that fruit trees have a considerably longer potential lifespan than is commonly believed. As human beings, our own lifespan has increased considerably thanks to medical science. The same is true for trees, even though not much research has been dedicated specifically to their ageing.
But there is no doubt that older fruit trees is a fascinating subject. The real gap in our understanding of the biology of older trees is that we don’t have detailed knowledge of how the various soil fungi interact with the tree’s feeding roots. All I know from experience is that the tree’s health status is directly related to the fertility of the top soil. Another important aspect is regularity of care. Older trees that have been neglected for many years can be improved, but to a lesser extent compared with trees which have been looked after on a regular basis.
Before we get down to the details, I would just like to reflect on my own personal experience with old fruit trees. Working with them on a regular basis gives a real feel of companionship with these living organisms, which, like me, are ageing, changing over the course of time, learning to deal with the changing environment around them. It generates a feeling of mutual respect and loyalty.
What can you do with an old fruit tree?
A lot has been said and written about the health and welfare of fruit trees in general. However very little attention has been paid to older fruit trees, which are supposed to be past their best. This generally means fruit trees which are over 25 or 30 years old. By this stage, fruit trees will probably be no longer productive: fruiting has become an irregular event and often, after a reasonable crop, the following year there is little to harvest, and what there may be on the tree is not suitable for the retail trade.
As a fruit tree ages, there are three approaches on how to deal with it. It can be left to grow and age naturally, and in this case it can become a feature in a garden, maintained primarily for its visual interest and the blossom. As it gets larger it will become increasingly difficult to thin, prune and pick. Alternatively, it can be removed and replaced with a new tree of a different sort. The third solution is to work progressively on the tree to keep it a height at which it can be looked after without the use of ladders, and treat it in such a way as to keep it in regular production.
Here I will present the techniques used to keep older trees in production, in good health and at manageable size. They are the techniques developed from practical experience. As I am very interested in looking after older trees, I have kept about 30 apples trees in cultivation – normally in a commercial orchard, trees of this age would be grubbed and replaced – that are now about 45 years old. These trees are on MM106 rootstock. The soil is a good loam and has been drained properly. The roots go quite deep and the trees have never have shown serious drought symptoms. They were planted 5 yards apart and the trees reached a height of 12-14 feet by the time that they were about 15 years old. There are different varieties, and they cropped regularly until year 20. After that point, cropping declined in output as well as fruit quality.
Just like human beings, fruit trees, as they age, clearly show lower levels of energy. Is there anything we as growers can do to help the tree to maintain their vigour, enabling them to produce a worthwhile crop year after year? In my experience there is.
The main actions are thinning the fruitlets early in the growing season, in early June, and performing summer pruning. But here is a list of the principal factors involved.
The 6 factors in keeping older trees in production
- Fruit thinning at a very early stage. This enables the tree to dedicate sufficient resources to the growth and ripening of the fruit.
- Reduce the size of the canopy. This should be done only in the summer.
- Stop winter pruning altogether.
- Adjust nutrition.
- Make sure that 2-year old wood is fully illuminated.
- Reduce final fruit numbers in July.
However, sometimes the problem encountered by a gardener is finding a tree that has gone out of control and has to be brought back to a manageable state. This requires work performed over at least 3 years, as I will describe in the next section.
In our current garden, to which we moved 25 years ago, we have 40 trees that were planted 70 years ago as part of a commercial orchard. When we moved there, those trees had been abandoned and had been left on one side of the drive. Over the course of the last three years I have enjoyed bringing them back to good health, and they are now producing fruit again. Their canopies are open to allow the entrance of sunlight.
These trees had been left to their own devices. Normally, as part of a commercial orchard, they would have been grubbed. But a careful examination showed that they were basically healthy. There was very little canker or any other serious diseases in the basic framework. There were no major problems with the insect population, except for too many woolly aphids. That meant that there were satisfactory levels of the beneficial natural predators which were keeping the aphids and other parasites under control. The bark on the trunks looked very healthy, and in fact that’s where the woolly aphids were overwintering. That’s why the application of winter wash, to the point of run off, was essential as a routine treatment to stop woolly aphids getting out of control.
The last basic health check was on the foliage, in other words the leaves of the trees’ canopy. It looked fine. New shoot growth was sufficiently vigorous to continue the ongoing process of replacement for the older cropping wood and, by means of the leaves, to feed a reasonable crop of fruit.
Restoring old fruit trees – time scale
There are two fundamental considerations before starting work on renovating an old fruit tree.
The first regards drainage. The soil must be well-drained. If the tree has a lot of dead wood, this is an indicator that there may be drainage problems. Standing water in the soil suffocates the roots by preventing oxygen uptake, causing a decline in the roots’ efficiency and hence the death of parts of the tree. If the soil is not well drained, there is no point in dedicating effort to restoring the tree. Apart from excessive dead wood, there are two other indications. If the trunk of the tree turns reddish instead of its usual healthy grey, it can be a sign of bad drainage, or land suffering from a compacted soil pan; and likewise, if the tree is particularly susceptible to canker.
The second regards timescale. Restoring an old fruit tree is a three-year process. In the first year, you work on the basic framework as described below. In the second year, you work on the external part of the canopy. In the third year, you cut back the new wood that has developed.
If you try to do everything in one year, the tree will react very strongly, throwing out large amounts of new wood that will be very difficult to control.
Year 1 – basic framework pruning
Once we have established that the soil is liked by the tree and the roots are healthy, and we have seen that the tree’s basic health, expressed in its foliage and bark colour, is all satisfactory, we can work on its framework. The restructuring of the basic framework is best done during the winter months.
If the tree has been neglected for many years, it is likely that the canopy has gone out of control, with too many branches and too much foliage, shading the inner structure, preventing efficient photosynthesis and therefore inhibiting good cropping.
Take a look at the tree and ask: is it capable of feeding its current structure, or are the lower branches beginning to lose vigour? Or, to put it another way, is the current structure too large for the tree to maintain?
Identify the basic structure. If it is a central leader tree, identify the vertical leader. Other branches may be growing nearly vertically alongside, and these will probably have to be removed. Count how many basic frame branches there are at present. These should be reduced to 4 or 5.
If the tree started life as an open centre tree, then it is best to retain that type of structure. When trees get older, what often happens is that the top branches last the longest, while the lower branches gradually lose vigour and eventually die. The skill therefore is to assess which branches are most suitable for retaining as part of the re-vitalised basic framework of branches.
All these considerations will enable you to decide which major branches to be removed. It is best to make a few large cuts, removing a complete branch with all its attendant structure, rather than many cuts on twigs and small branches. To stop major infections occurring, these big saw cuts will need to be sealed properly with a specially-designed wood sealing compound (“Heal and Seal”).
Year 2 – Canopy pruning
Once the basic framework has been restored in winter, the next step, performed the following year, is to improve the external parts of the canopy. This is best done by the end of May, when the blossom period is over, and during the summer months. The risk of fungal infections is then lower.
Try to assess the state of health of the smaller-diameter limbs, in other words the branches that form the outer layers of the tree canopy. In neglected fruit trees, there will usually be far too many of them.
These branches will have to be reduced in numbers. This is essential, because each branch of the tree canopy needs to receive direct sunlight, so that all of its leaves can create the energy that the tree needs, by means of the process of photosynthesis.
How do you decide which canopy branches to remove? The following branches have to be removed; any crossing branches (a branch that crosses above or below another branch); a branch that creates shade over a lower permanent branch; any wood that is positioned near the trunk and has lost all its leaf because it is permanently in the shade; any dead or diseased branches, such as those badly affected by canker.
Do not cut back the remaining branches.
Year 3 – Conventional maintenance pruning
In early March of the third year, you can cut back some of the surplus new wood that has developed over the preceding two years. There may be some vertical shoots in the top part of the tree competing with the central leader, which can be removed. Identify the previous year’s growth on shoots in the lower part of the tree and prune back about a third. Take care to leave enough young laterals, young side shoots growing from the main lateral branches, as they will bear fruit buds next year. Only remove some if they are too crowded, closer than about 6 inches, 15 cm, at the base.
From now on you can follow the instructions provided on our fruit tree pruning page.
Keep an eye on the tree during the spring and summer. It will have to be kept free from fungi and pests.
Watch the foliage for signs of distress. Water the tree well in dry spells, and apply foliar feed if necessary.
After these renovation operations, the tree will need 3 years to settle down again. But it will thank you for it.
Problems encountered with older fruit trees
Why does a fruit tree suffer as it gets older? We are accustomed to seeing trees in the wild or in the forest that grow, reach maturity, and continue living without any apparent problems.
But fruit trees planted by men are in a completely different situation. They usually have dwarfing or semi-dwarfing rootstocks that have a limited capacity for taking up water and nutrients. They are often surrounded by a lot of empty space, and so don’t benefit from the company of other trees that shade the ground and help prevent the growth of competing grass and weeds. Here are some of the situations that often occur with older fruit trees – beyond the 10-15-year mark – in gardens or old orchards:
- Lack of maintenance. Many people only take a look at the tree to see whether there is any fruit on it. If there is no fruit, the tree receives no attention for another year.
- Weeds. Poor maintenance of the area around the tree. There is often a serious lack of moisture due to dominant weed species such as grass.
Watch a video tutorial on the effect of weeds on fruit trees.
- Root death. This is often caused by bad drainage. This can become a dominant factor as the tree gets older, with a canopy that is getting progressively larger.
- Mineral deficiencies. These are often visible from symptoms that can be seen on the leaves.
- Fungal diseases. Once they take hold, they usually get progressively worse. They include tree canker, bacterial canker, peach leaf curl, armillaria root rot.
- Recurrent pest damage. If the insects causing the damage each year are not dealt with properly, their effects become progressively worse.
- Lack of predator insects. If the presence of beneficial predatory insects or fungi is not encouraged, the tree can’t cope with parasites.
- Lack of nutrition. A tree has a constant need for minerals and organic substances. In the wild, a continuous supply of these substances is provided by the natural cycle of plant growth, death and bacterial decomposition. In a garden, all this material is carefully removed and so the soil becomes depleted.
- Incorrect winter or summer pruning. The consequences of pruning change as the tree gets older and so these operations should be carefully calibrated to prevent unwanted side effects.
- Competition. It is important to understand the competitive forces in the immediate surroundings, such as the effect of neighbouring trees. Trees in nearby hedges or on the other side of the fence in the neighbour’s garden may be competing for resources, or they may have beneficial symbiotic effects on aspects such as pollination.
How to move an older free-growing tree
I have never forgotten my infancy and youth with my parents in Holland, and how home-grown fruit from our garden helped us during the hardest years of World War II. For me, trees became not just a resource, but objects of fascination and attention. In the garden there were some trees that I became very fond of, as a result of their character or their special beauty. And so when we moved house – which, as for all of us, happened quite frequently – I wanted to take those special trees with us. That was a very interesting exercise.
When a fruit tree has been growing freely in a garden or orchard, and has become a treasured possession because of its special characteristics, beauty or just because it is an inherent part of a landscape dear to us, moving it is more of a problem. It can be done successfully, but only if careful attention is dedicated to the fundamental details.
However, moving an older tree is not a task to be taken lightly. It is not something that you can do yourself with a spade. It is a heavy task that requires a contractor with lifting gear and horticultural skill. Before even considering moving a tree, it is essential to check that the destination has all the right characteristics, above all the type of soil, and good drainage.
The tree has to be lifted out with a sufficient amount of undisturbed soil, and then moved to its new destination. The most important point to remember is that the uptake of moisture and nutrients takes place predominantly via the very fine hair roots and not via the big holding roots. So it is vital that the soil immediately close to the trunk is lifted as a whole. In that way the tree is able to continue to take up moisture from the soil. By transplanting the tree with a substantial amount of undisturbed soil, it is possible not to have to excessively reduce the canopy of the tree. All the same, the canopy should be no more than 50% wider than the diameter of the undisturbed soil base. Make sure the planting hole is of the correct size and depth.
Secondly the best time to move a larger/older tree is in the period mid-November-mid-March. That gives the tree plenty of time to re-establish its roots, before spring arrives. Staking is of course of paramount importance. Watering the transplanted tree throughout the spring and the summer on a weekly basis is an absolute must.
There is another factor to be taken into consideration. As fruit trees get older, they are more vulnerable to various pests and diseases, and this risk is vastly increased if they are transplanted into a new location.
Slow-growing trees such as olive trees are easier to move successfully, when compared to other types, for example a pear tree. Some types of trees, such as green gage, plum or cherry, are by nature trees with a relatively short life span. I would recommend not trying to move these trees at all once they have passed the 8-10 year mark. The risk is too high, and it is not worth the effort.
How to get a large tree quickly
One reason why people would like to take their older fruit trees with them to a new garden is because they are already a good size. They are a desirable feature in the garden. But there is an alternative. You can buy tall trees from specialist nurseries. These trees are not cheap, but they are worth the money, provided the planting and after-care is carried out properly. It is essential that the tree is not root bound. If you are a member of the RHS, you can ask them which nurseries they recommend. Personally I can recommend Barcham trees Plc, Ely, in Cambridgeshire.
At these nurseries, the trees are grown in the open field during the first 2-3 years. After that period they are transferred to special containers which prevent the roots from circulating around the outer rim. The trees are then grown on to a substantial size. Provided these trees are frequently watered and looked after properly during the growing season, they will do well after transplanting.
How to move an older potted tree
If the tree has grown in a large pot in which the root system has been restricted to the volume of soil in the container, they can be moved relatively easily. Larger fruit trees such as apple, pear, green gage, plum or cherry should be grown in a specific container which avoids the problem of spiralling roots. This enables them to be moved with a low degree of risk. They can also be transplanted into the soil at a new site and, with the right care, rapid re-establishment will be ensured.
How to transplant a tree from a container
Whether you are moving your own potted tree, or you have bought a tall tree from a specialist nursery, it can be planted at the new location at any time of year. However, do not plant the tree if the soil conditions are not right. Compacted soil, or soil which is too alkaline or too acid, will need to be corrected before the tree is planted.
Here are the essential points for transplanting a potted tree:
- Soil analysis. A soil analysis is a very good investment: contact the RHS at Wisley for a soil test.
- Correct planting technique. Follow our tree planting suggestions when transplanting the tree.
Watch a video tutorial on how to plant a fruit tree.
- Watering. Make sure the tree is watered weekly when it has been planted during the spring or summer months. Do not over-water.
- Weed-free. Make sure that there is an area 1 metre in diameter around the trunk of the tree that is kept completely free from grass and weeds. The best way to do this is to visit the tree every week and manually remove any grass and weeds that have grown.
- Support for the tree. Stake the tree well. This is important because the roots have to be left in peace to do their work.
- Tree-tie. Adjust the tie every year, allowing extra room for the tree trunk as it expands.
- Tree guard. Protect the trunk of the tree with an appropriate tree guard to prevent damage by deer, muntjacs etc.
Watch a video tutorial on how to look after a newly-planted fruit tree.