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Fruit : Apples

Apple varieties | Rootstocks | Choosing tree shape | Planting | Training | Pruning | Winter pruning | Summer pruning | Feeding apple trees | Unfruitful and neglected trees | Fruit thinning | Picking | Re-grafting old apple trees | Weeds, pests and diseases

Apple varieties

Apple blossom awaiting pollination

Apple blossom awaiting pollination

Apples will not crop well on exposed sites; near the coast, or over 200 metres above sea level. Do not plant on a north-facing slope, or at the bottom of any slope where frost might gather.

Choose a warm, sheltered spot, not shaded in any way – especially by large trees that would rob the apple trees of food, water and light. Too much shelter, on the other hand, increases the risk of disease attack, because the foliage stays damp longer.

The ideal soil is deep, fertile, well-drained but moisture-retentive, and slightly acidic. But apple trees grow well on most soils, as long as they are well-drained. They can suffer potash deficiency on dry limy soils and, by contrast, tend to be over vigorous and prone to disease on heavy, limy soils.

Peaty soils are too generally too wet and infertile for apples. Replace poor soil, if necessary, to a depth of about 30 centimetres.

There are hundreds, possibly thousands, of apple varieties, and a wider range is probably available now that at any time in the past, because many old varieties have been revived. It is worth trying some of these if the space is available. But if you have space for only a few trees, then the choice will be far more restricted.

Apple varieties divide into cooking apples and dessert apples. Cooking apples are acidic to taste and their crumbles when cooked. Although the flesh of dessert varieties stays intact, they can be used for cooking too. It may be decided not to bother with a cooking variety, if space is limited. If it is desired to have cooking apples, ‘Bramley's Seedling' is the only variety to consider, as it crops and stores well.

Of dessert apples, the early-fruiting ‘Discovery' is excellent, and disease resistant, with luscious red fruit that can be eaten from the third week of August. ‘Scrumptious' is a new early variety, bred from ‘Discovery', that is showing promise. ‘Lord Lambourne' is an old variety for September, very reliable, with some self-fertility, disease-resistant and grows well in less favoured areas in the west and north.

For a late variety, to use from October to December, but not to store much longer, ‘Red Devil' is red with pink-stained flesh, disease resistant, and self-fertile. ‘Elstar' is a good cropper to use until January and ‘Idared' has scab resistance and stores until early spring. ‘Winston' is very disease resistant, self-fertile, green flushed red and stores very well until March, the colour and flavour developing. Trees with several varieties grafted on, called ‘family trees', are available.

Rootstocks

 While the rootstock on which the tree is grafted will affect the size to which it will grow, most trees are sold on the dwarfing rootstocks M9, or M26 which is somewhat more vigorous. MM106 is more vigorous again and makes a tree that will grow to three metres or more in width. Least vigorous of all are trees on M27, which is suitable for very small spaces and trees to grow in large pots.

A nice set of apples on a young tree

A nice set of apples on a young tree

Choosing tree shape

Tree shape should be chosen to suit the garden. If space is very limited, the restricted tree shapes – cordon, fan and espalier – are ideal. Cordons are grown on wires between posts. Use four wires, each 30 centimetres apart, the first at 45 centimetres above ground level. Support the wires on strong wooden or steel posts, about 5 metres apart.

Fans and espaliers can also be grown on wires, or on walls or fences. The restricted tree shapes take up little space – trees will be only about 45 centimetres deep and about 180 centimetres high. These shapes are suitable only for dessert varieties.

Where there is a little more space, free-standing spindle–bush trees can be grown. These are supported only by a strong 180 centimetres stake. Spindle bush trees are kept to about 200 centimetres high and about 150-200 centimetres wide. Both spindle-bush trees and restricted trees must have dwarfing rootstocks to keep them small.

If there is plenty of space, open-centre bush trees can be grown. Kept to about 3 metres high and about 3 metres in spread, these trees should have semi-dwarfing rootstocks. Some old orchards have large trees, up to 8 metres high, grown on vigorous rootstocks, which are no longer used, but these old trees are very difficult to prune, spray and pick fruit from.

Planting

November is the best month for planting but apple trees can be planted until the end of March. Decide on the planting site, tree shape and varieties. Remove, or spray off, the existing grass or weeds and dig the soil over a square metre or so. Incorporate a couple of bucketfuls of well-rotted manure or compost at the site for each tree.

Buy the trees and soak the roots before planting. Dig holes 45 centimetres wide and 30 centimetres deep. Drive a stake in each hole to support the young trees. Trim any damaged roots. Test the tree in the hole for depth, and plant at the same depth as the soil mark on the stem. Fill in and firm gently. Tie each tree to its stake.

Space cordon trees about 150 centimetres apart; fan, espaliers and spindle bushes about 240 centimetres apart; and open-centre bushes about 4 metres apart. The quickest to bear fruit are cordons and spindle bushes – often in the season after planting. The more vigorous cooking varieties, trained as open-centre bushes, may take up to ten years to crop well – especially on heavy soils.

Training

The training procedure used will depend on which tree shape has been chosen. Restricted trees – cordons, espaliers and fans – are often bought with the initial training done. Simply tie the shoots into position to hold the existing shape. Surplus shoots, and those that are badly placed and cannot be tied into position, should be removed.

To train trees from scratch, they should be no more than two years old. The wood is still pliable and the young shoots can be tied into position as they grow. Bare-root trees are usually only two years old, but container-grown trees can be several years old and may already have bad shape that is difficult to correct.

For spindle bush trees, tie-in the main leader to the stake. Allow both the leader and the side shoots to develop. In July, tie the side-shoots down into a horizontal position to induce early cropping.

In the winter after planting, release the ties and shorten the first year’s growth by about one-third – both leader and side-shoots. Repeat this procedure in subsequent years until the spindle bush shape develops. Maintain the central stem from which the horizontal side branches arise. Do not allow rival leaders to develop.

For open centre bush trees, shorten the main shoot to about 75 centimetres above ground level. Select four or five of the side shoots that develop, if these are not already present. Shorten these to half their length each year, allowing them to become the main framework branches.

Do not allow a central main leader to develop. Remove branches that tend to grow toward the centre of the tree. This is kept open to let in light and air.

Pruning

When all the young apple trees have been given their initial training for four or five years to form their shape, annual pruning will be necessary to maintain the desired shape and to promote the production of good quality fruit.

Apple trees carry the largest, sweetest fruit on branches between two and five years old. To maintain a fair proportion of branches of this age, some of the oldest branches in the tree are pruned out each year and younger ones allowed to take their place. The idea of replacement is the key to pruning apple trees.

There are two periods for pruning – December/January and July/August. Winter pruning encourages growth of new shoots. Summer pruning discourages growth.

Winter pruning

This is the main pruning period for the free-standing, open centre bush and spindle-bush trees. Start by removing all dead, damaged or diseased branches. Next, select two or three fairly sizeable branches from among the oldest on the tree.

Make the choice by reference to their position, bearing in mind the correct shape of the tree and the existence of a younger replacement branch. Usually the choice is easy, because an old branch may be crowding a younger one.

Having removed some old wood, then remove, or shorten, all weak and spindly shoots. The remaining strong, young shoots will eventually make good fruiting wood. Shorten these by about one-third of their length. These general guidelines suit all types of bush trees.

For the restricted trees, such as cordons, espaliers or fans, less winter pruning is practised. Heavy pruning in winter would encourage them to grow away from their restricted shapes. In winter, just prune out a few old branches, exhausted old fruit spurs and weak, spindly shoots.

Summer pruning

Restricted trees produce young shoots each summer. About mid-July, begin shortening back the stronger shoots to four or five leaves, at the rate of a few each week or so, until September. Do not bother shortening weak shoots – these can be removed in winter.

Removing some of the current year’s growth

Removing some of the current year’s growth

Bush trees that are very vigorous, but unfruitful, should get summer pruning, and no winter pruning for a few years – until cropping starts.

Feeding apple trees

Apple trees should get 70 grams of general fertiliser, or Fruit Fertiliser, per square metre in February or March each year. The area of the spread of the branches should be used to calculate the quantity. Even quite small trees will need at least 300 grams each on this basis. Fertiliser is essential for good growth and cropping.

If the trees have tended to be vigorous and not produce much fruit, apply 35 grams of sulphate of potash per square metre each year for three years instead, especially on heavy, limy soils.

Unfruitful and neglected trees

Old, over-grown trees can be brought back into production by pruning, feeding and spraying. Prune out some of the old wood and thin out the branches. Feed and spray as normal. Old trees that have deteriorated too much, or are of a bad variety, can be grafted with a new variety.

Apple trees can be unfruitful for a variety of reasons, usually the site is wrong, the soil is poor, or there is no cross-pollination. If these reasons are eliminated and the trees have grown very strongly, producing wood and leaves but few flowers or fruit, the problem is over-vigorous growth. This may have been caused by too-severe winter pruning, or by wrong feeding, and it is a tendency of vigorous varieties planted in heavy, fertile soils.

Bark-ringing can be used as a remedy. This involves removing a 1 centimetre strip of bark from around the stem at blossom time. Seal the cut surface with tape or pruning paint. The restriction in the flow of sap encourages the production of flower buds, and fruit eventually.

Root pruning is another remedy for over-vigorous growth and poor cropping. This involves finding three or four major roots, removing the soil and cutting through the roots.

Fruit thinning

Established apple trees often produce too many small fruits of poor flavour because the tree has not the vigour to swell them all. A certain amount of natural thinning takes place. Only those apples with several seeds actually develop to maturity. Many just drop off after initial development. This usually happens in early July, although it is called the ‘June drop’.

Wait until mid-July when the ‘June drop’ is past. If surplus fruit remains, thin it out to leave one apple for every 10 centimetres of branch length. The apples may not be spaced evenly along the branch, but this ratio can be used as a guide to numbers.

Picking

Apples ripen on the tree and should not be allowed to fall. Pick the fruit when the stalk parts easily. Some varieties must be used quickly – ‘James Grieve’, ‘Worcester Pearmain’, for instance. Others keep for a few weeks – ‘Laxton’s Superb’ and ‘Jonathan’. Some varieties keep well up to March/April – ‘Golden Delicious’, ‘Bramley’s Seedling’. ‘Crispin’, ‘Idared’ and ‘Queen Cox’.

‘Lord Lambourne’ apples

‘Lord Lambourne’ apples

The keeping varieties can be stored in polythene bags with the top left untied and with a few small holes in the bag to allow air exchange. Store only clean, unbruised fruit of varieties known for their keeping qualities. If a refrigerator is available, the fruit can be stored at a low setting.

Re-grafting old apple trees

In December or January, collect young shoots of the new variety. These should be about 30 centimetres long. Tie them into a bundle and place it in a cool corner of the garden with the bottom 7.5 centimetres in the soil. In mid-April, cut down the main branches of the old trees, leaving them about 90 centimetres long. Remove any small branches.

Make a sloping cut on one of the young shoots above the soil mark where the bunch was in the ground. Trim the top end to leave the piece about 15 centimetres long. Make a slit in the bark of a branch stump of the old tree. Insert the prepared shoot, making sure the cut surface is in good contact with the wood beneath the bark of the old branch.

Tie the grafted shoot tightly in place and seal all the cut surfaces with grafting wax, such as Tenax, or wrap thin strips of polythene around to make a seal. Cut the ties as soon as the buds break. Train the new shoots to replace those removed. The first fruit will be produced two years later.

Weeds, pests and diseases

For at least the first few years after planting, keep the ground around the trees free of weeds and grass. Dwarf trees compete poorly with grass and may need to be kept weed free for one metre diameter at least.  As the trees get bigger, grass can be grown underneath, but it should be kept short.

Codling moth larva in an apple

Codling moth larva in an apple

Codling moth grubs hatch from eggs laid on the young fruit and bore in through the ‘eye’. Feeding and growing inside, they eventually eat their way out. Affected apples ripen prematurely and fall off. The pest is very common in town gardens and precautions are often necessary.

Greenflies cause stunting of shoots and fruit. A kind of greenflies – woolly aphid – produces woolly masses on the branches, and severely weakens the tree. Control is usually necessary.

Caterpillars may attack the leaves, but damage is usually slight. Red spider mites may attack in warm summers, causing the leaves to go bronze. If damage is severe, control might be necessary. Bullfinches may attack buds. Netting might be necessary in rural areas.

Apple scab disease attacks leaves, young shoots and fruit – causing black or brown scabs on the latter which sometimes crack. Spraying will be necessary, especially in wet years and wet localities.

Use resistant varieties such as ‘Discovery', ‘Katy' and ‘Lord Lambourne'. Spray susceptible varieties at bud-burst, in late March or early April, with Captan or Systemic Fungicide Control or Fungus Clear 2. Repeat the spray at least three times between then and the end of June. In a wet year, and in wet localities, more applications can be necessary.

Apple scab disease

Apple scab disease

Apple canker is a serious disease causing sunken cankers on branches and trunk. Branches may die. Avoid injury and control apple scab which creates an entry for canker on young shots. Prune out affected branches.

Powdery mildew causes whitish discoloration of young leaves and shoots. A bad attack weakens the tree. Prune out affected shoots when noticed in May and June.

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