Propagating Fruit Trees and Bushes

Propagating Fruit Trees

Replacement and Replenishment

Growing replacement plants is quite simple for most of the soft fruits, provided you can get cuttings from healthy bushes. Unfortunately, your own plants will probably need replacing because they have picked up disease and are not a source of suitable material. This is particularly so for blackcurrants, raspberries and strawberries, which tend to suffer from virus diseases.

strawberries As a general rule, eradicate any of these plants you inherit with a garden, and periodically replace old with new. Strawberries need to be replaced every third or fourth year, but you can root runners from healthy plants to get up to a dozen years from a batch before buying in new stock. Blackcurrants and raspberries need replacing after ten to fifteen years. The other currants and gooseberries last a couple of decades, and most of the tree fruits we plant will still be producing crops long after we are pushing up daisies.

If you want multiple plants of one variety of soft fruit, buy one good certified virus-free plant and take twice as many cuttings from it as you need. Hardwood cuttings of about a foot long, taken in the autumn from healthy new growth, should produce excellent fruiting plants in under two years. Rub off the buds from the lower half of each cutting. Push the cuttings a hand’s breadth deep and a foot apart into clean, gritty soil in the open ground on a seed, vegetable or nursery bed. On heavy soils, force sharp sand into the bottom of a slit trench and plant the cuttings in this. Firm them really well. Keep them sheltered from the worst winds — cloche them during hard winters. Keep the soil weeded and moist and new plants will be ready to be moved out the following autumn.

Blackcurrants are the easiest to raise from cuttings. Each plant is grown as a stool with many shoots from ground level, so do not rub off the buds on blackcurrant cuttings. Other currants and grapes are very easy too. Gooseberries fairly so. All the blackberry family and hybrids can be grown from the tips of the canes allowed to root into pots in late summer. Raspberries produce suckers all over the place, choose strong ones with fat underground buds and a mass of fibrous roots, transplant these in autumn and cut them back to knee high.

Strawberry runners coming from clean, deflowered, vigorous plants are easily rooted into pots in early summer and can then be planted out in late summer to fruit well the following year. Don’t bother trying to root cuttings from tree fruits — they do not take easily, and even if they do the resulting plants are not controlled by a dwarfing rootstock. It’s also hardly worthwhile growing most common fruits from seed, because they take a long time and are not very good. Seedling raspberry, Japanese wineberry and currant plants are less disappointing than most.

Above all, it is absolutely essential you use healthy plants for propagating, so avoid obviously dubious specimens and especially avoid old blackcurrants, raspberries and strawberries as these are prone to more disease problems than most others. Remember not to plant your new fruit crop on exactly the same site as the old, because they are likely to suffer from replant disease.


Companion plants

It is essential to keep a clear circle of at least a pace or two around a tree or bush for the first few years, so it can establish without any competition. The bigger the mulched or weeded area the quicker the tree establishes. Having other plants nearby initially inevitably leads to poorer growth and lower, later yields. So don’t plant companion plants until after the fruit has established. Companion plants can be of immense benefit, bringing in and maintaining larger populations of predators and pollinators. Rosemary, thyme and sage, lavender, chives, garlic, Limnanthes douglasii, Convolvulus tricolor and nasturtiums are all of particular benefit to fruit trees and bushes. Red dead nettles and stinging nettles, docks and thistles also help, but these are not so pretty.

Traditionally, orchards were furnished with grass, alfalfa and clover as companion crops, though pears were only grassed if over vigorous. Grassing down must never be done until the trees are well established anyway, then it is worthwhile for the appearance and reduced labour. The grass competes with the trees, but if the clippings are returned their fertility returns, and the sward prevents soil erosion. Orchards need cutting at least once a year to prevent shrubby weeds taking over. Grassing down increases the danger from spring frosts because bare soil keeps the air above warmer at night.


Planting

Sprays of seaweed solution will be of immense benefit during the first year and should be done routinely at monthly intervals. Never let trees or bushes fruit in their first year, because this diverts energy from the roots where it is needed. Deflower them as soon as the petals fade, though it is permissible to allow one fruit only per tree or bush for identification purposes.


Training methods

For the least effort try to grow most fruits as trees; either standards, half standards or bushes. Pruning is minimal with only ingrowing, rubbing and diseased growths needing to be removed. Big trees do take up a lot of space and are slightly slow to start producing, so for small areas or where many varieties are desired then go for dwarfed and trained forms of fruit. However, these require much more work and need permanent supports. They give large early returns and the quality of fruit is higher, but they cannot be as neglected without dire results.

Cordons are effectively one branch of a fruit tree grafted onto a dwarfing rootstock. They are trained at an angle to make more efficient use of space, but need posts and wires to support them all their life. They can be planted at close intervals allowing many different varieties in a short run, say, along the side of a path. Though each cordon produces much less than a bush or tree, they produce more per acre and the quality can be much better. Apples and pears are very suitable for cordon training as are red and white currants and gooseberries.

espaliers Espaliers have a vertical main stem off which are trained several horizontal tiers. They make very attractive forms for enhancing a wall or used as a screen. Step-over espaliers have only one low tier running parallel to the ground and a foot or so high. They are of most use in the smallest of gardens. Espalier treatment is suitable for most apples and pears, but many other tree fruits are more difficult to train this way and are easier as fans.

Fans have all the branches radiating from the top of a short trunk and can look very attractive, they are most suited to the stone fruits, which are difficult to train as espaliers.

Forming the initial framework of trained fruit is not difficult and if left to the nurseryman will cost you more than buying unformed maiden trees. It is more satisfying to do it all yourself, but does take time and some thought. Generally, once the shape has been established, pruning is fairly simple. The main exception is trained stone fruits, which need serious reworking almost every year.


Winter pruning

Usually done initially to form the shape of a tree as it stimulates replacement growth, but too often excessive winter pruning is done in place of summer. Remove crossing, rubbing and dangerous, dead and unhealthy growths as soon as they are spotted — usually when the branches are bare. However, winter pruning is best avoided for the stone fruits, such as plums, as these may then be attacked by silver leaf disease. Winter pruning is worth the risk when major surgery is being carried out, because if it is performed during summer the tree may die of shock. Also, when vigour has been lost, winter pruning and feeding may stimulate new growths. Overly hard winter pruning may cause ill-placed replacement growths, such as the ‘hedgehog look’ of ‘water’ shoots seen in gardens where the saw and secateurs are used too often.


Summer pruning

Often ignored, this is a far more useful and important method for looking after trained trees and soft fruit than winter pruning. It does not stimulate growth, but fruiting. Summer pruning is simply the removal of half to three-quarters of each new shoot once mid-summer is past. This allows air and light access and checks growth, encouraging the formation of fruit buds. However, where the plant is still being allowed to expand to fill space available then shoots going in the desired directions are not cut off. These may be shortened in winter to encourage side shoots to develop.

Soft fruit pruning is easier than for tree fruit and the plants are much quicker to respond to training, so they are ideal for gaining experience. Those grown as stools, such as blackcurrants, are the simplest. Immediately after fruiting cut one-third of all the branches back to ground level starting with the oldest stems. Raspberries, blackberries and their hybrids are also normally grown as stools, with young growth being encouraged from ground level to replace the old on an annual basis. The oldest are cut away after fruiting to leave the new — this simultaneously removes most pest and disease problems. Tying these young canes down on either, or to one, side then allows the next year’s new flush to grow straight up and keeps them clean of disease spores dropping from the older.

The stone fruits, when trained, are treated the same way with constant removal and replenishment of young shoots coming from a central core frame. Red and white currants are very forgiving and can be grown in almost any form imaginable, as can gooseberries, which make for easier picking when well trained. All of these require their young growths cutting back by half to three-quarters in summer and then again by a bit more in winter. They are best pruned to form an open goblet shape, or failing that as bushes on short legs, so that the sun can penetrate and air can circulate, which helps keep them disease free. If you want to grow prize berries, grow them as cordons and feed the soil heavily.


Inducing regular fruiting

You may find the situation where your trees are established and growing well, but they fail to flower and fruit. If there are strongly growing vertical branches then attach lines near the tips and pull them gently down from the vertical. This checks the sap flow and induces fruiting more effectively than pruning. The branches can be kept bent by tying on weights. A plastic bottle part-filled with water is ideal because it is adjustable.

If flowers are prolific, but none sets, suspect the lack of a suitable pollinator and ‘borrow’ some sprays in bloom from friends’ trees and try pollinating with these. If any of the trials set fruit then graft a branch on.

Some fruit, especially apples, are biennial bearers, cropping only in alternate years. To get fruit every year, remove half or more of the fruits during the ‘on’ years, so that the tree is not exhausted; then it does not need a year off. Indeed, almost all the tree fruits, gooseberries and grapes will give bigger and better fruit if they are thinned every year. Fruit thinning is also the simplest way of improving the quality as the diseased and pest-ridden fruits can be removed and destroyed before the malady spreads. Thinning is best done after mid-summer, but before fruits have started to swell significantly and it should be done ruthlessly.

The plants can afford to give us plenty of fruit flesh to eat, it is only sugar and water — it is the seeds inside that exhaust the plant, taking proteins, fats and minerals. Reducing the number of fruits reduces the numbers of seeds the tree has to produce. It will still give the same weight of fruit, but each one will be bigger. Thinning twice is better still. Make the second thinning a month after the first to leave only perfect, well-positioned fruits. Three times thinning is worth the effort because the thinnings are by then large enough to use in the kitchen.


Annual maintenance

Visit every staked tree and check the tie regularly, at least twice a year. Also firm the ground around each new tree after hard frosts. Hygiene is essential, remove all diseased material as soon as it is spotted and burn or compost it, especially diseased fruits. Also inspect the fruit store and remove any infected material. All fruit trees and bushes benefit from being banded with sticky tree bands to catch the wingless pests that climb trunks to lay eggs. You need to band the stakes, posts and wires as well.

Top up mulches as fruit trees and bushes benefit immensely from these, and at least every third year they should be given sieved garden compost. During the winter, occasionally rake mulches and compost aside for a day or two so that birds can get at pests overwintering underneath. I find a monthly spraying of the orchard and fruitcage with seaweed solution from early spring to mid-summer is beneficial because it promotes vigour and disease resistance.


Watering

This is absolutely vital for fruits in containers which need watering three times a day in hot summers. Generally, watering is not as necessary for fruit as for vegetables, but it is always advantageous in dry years, especially for soft fruit, because two crops are threatened — this year’s fruit and next year’s buds. Fruits growing in borders next to walls or in dry corners will benefit the most from watering.

The critical thing with any plant is to water before it suffers or wilts. Fruitlets often drop in late spring as the soil dries out, so apply mulches early and water well before the plant shows any distress. Warm water will soak into dry soil better than cold, and ice cubes melt so slowly they will wet even really dried out peat. Never water in dribs and drabs; give an occasional good long soaking instead. However, take care not to waterlog plants, especially when growth is slow, since this can starve their roots of air. Water well before the fruits start to swell — do not leave it too late or the skins harden as growth slows and then the fruits split when growth resumes.

Given the choice, water early in the day rather than later, and rainwater is much better than water from the tap. This is more important for fruit growing in containers, as rainwater contains less dissolved salts which tend to build up in container compost as the water evaporates.

05. January 2011 by admin
Categories: Featured, Fruit Gardening, Propagation | Tags: , | Comments Off on Propagating Fruit Trees and Bushes

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