Apple

(Malus domestica) (Malus pumila, Pyrus malus)

Introduction

The Apple is the is the most widely cultivated of the temperate zone tree fruit because it is the most dependable and reliable. A huge number of varieties have been produced over the years, with varieties for eating fresh, varieties for cooking and varieties for making hard cider. There are varieties that do well in every temperate climate, from frigid Russia to warm Israel. I have never been a big fan of bland commercially produced apples, but a home grown Golden Delicious at its peak is one of the highlights of my gardening year (an apple pie made with Bramley apples is another).

History

The domesticated apple has several parents, but it is now believed to be mainly descended from Malus Sieversii which is native to Kazakhstan. In its native land there were once extensive forests consisting of wild apple trees (mixed with pear and apricot) of every imaginable shape and size and color and flavor. It’s been estimated that modern apple varieties only contain about 20% of the genetic variety available in apples, while these forests contain the other 80%. The city of Alma Ata (which means father of apples) lies on the silk road in the center of this region and it has been suggested that apples travelled along this road to other parts of the world. Predictably the modern world is taking its toll and rapidly destroying these forests.

The apple is a tasty and reliably productive crop and at one time almost every country garden had at least one tree. It was extremely important in colonial America where the trees were grown almost entirely to make hard cider (they were one of the most profitable crops).

Nutritional content:

A medium sized apple contains

Calories 81 Carbohydrate 21 grams Dietary Fiber 4 grams Soluble Fiber  Insoluble fiber Calcium 10 mg Phosphorus 10 mg

Iron .25 mg Sodium 0.00 mg Potassium 159 mg Vitamin C 8 mg  Vitamin A 73 IU Folate 4 mcg

About Apple

Ease of growing: Easy (in the right climate)

Zones: 3 – 9

Size Standard – 40ft tall x 20-30ft wide

Semi-dwarf – 12-18ft tall x 12-18ft wide

Dwarf – 6 – 12ft tall x 6-12ft wide

Blooming period: March- April (sometimes May)

Fruiting period: July- October (November)

Chill requirements (number of hours at 32-45°F): 400-1000 hours or more (most need the higher amount)

Bearing age: 2-5 years after planting (depending on rootstock)

Life expectancy: 100 years for a standard (30-50 for dwarfs?).

Days to harvest: 100-200

Yield per plant: 30 – 200 lb (depending on variety and size of tree)

Ease of growing: Apples became so popular because they are easy to grow if they get the right conditions.

The trees are quite fast growing when young, though this slows considerably when they come into full bearing. Established trees can withstand a considerable amount of neglect and still bear worthwhile crops. A standard tree can live for a century or more and develops an attractive gnarled appearance with age. Trees on dwarfing rootstocks are not so long lived.

Apples have their share of potential problems with insects and diseases, but none are insurmountable.

Climate: Though there are apple varieties suited to every temperate climate, they do best in cool, moist, conditions, with winters that are cold enough to give them the required amount of winter chill. They are very hardy trees, with some varieties able to tolerate temperatures as low as -40°F. The sweetest dessert varieties need warm summers to produce the abundant sugar that makes sweet fruit.  

Site: Apples can tolerate light shade but are most productive in full sun. This is particularly important for the sweeter varieties, as they need that solar energy to make enough sugar. Not surprisingly cooking apples can tolerate more shade, as the fruit doesn’t need to get as sweet.

Where you place the trees is most significant in cold climates. The trees should not be planted in frost pockets (or behind frost dams) as a late frost can damage the flowers. The middle of a slope is a good spot (and not so good for other things) as it allows for good air drainage.

In windy areas a windbreak is helpful to protect the plants (and their insect pollinators) during the critical pollination period. However you want good air circulation as it means less frost and disease.

If your soil isn’t very well drained you might consider planting on a hillside, or on a mound.

Soil

pH: 6.0-7.0  

Apple trees can grow in most soil types (light or heavy), so long as they aren’t too wet. It doesn’t need to be highly fertile, as this can encourage vegetative growth at the expense of fruiting. The ideal soil will also be slightly acidic.

Site preparation: If your soil is very light you should incorporate lots of organic matter. The best way to do this is to dig the entire planting area and incorporate 3” of compost or aged manure. This is much better than simply amending the planting hole, as it encourages the roots to spread out.

It is no longer considered a good idea to amend the planting hole with nutrients and organic matter “to give the tree a head start”. The abundance of readily available nutrients may simply encourage the roots to stay in the planting hole, rather than spreading out like they should.

Spacing: How far apart you space the trees depends upon the ultimate size of the tree (obviously). This depends upon the type of rootstock used and can vary enormously. Dwarf plants could be as close as 6-10 ft apart, semi dwarfs 15-20ft apart, while standard trees might be 20-40ft apart. Apples should ideally be planted within 50ft of each other to ensure good cross-pollination.

Planting:

When: In mild winter areas dormant bare root trees are usually planted in January or February. In colder climates they wait a little later and plant in early spring. Mail order trees are available for a long period from fall to spring, but you should still plant at these times.

Plants in containers are convenient in that they can be planted at any time of year, but are more expensive than bare root plants and don’t usually do as well. In some cases they are simply unsold left over bare root stock that has been potted up (rather than discarded or sold cheaply) . These will often cost twice as much as bare root plants and usually won’t work as well (it depends how long they have been sitting).

How: Dig the planting hole 2‑3 times as wide as the root ball, to give the roots plenty of loose soil to grow into. You want the hole to be the same depth as the root ball (or roots if bare root), so it can be set into the ground at the same depth it was growing in the nursery. This is most easily measured by laying a stick across the hole to get the right height. The graft union should be 3-6” above the soil.

In poorly drained soils you may have to plant on a mound, to keep the collar of the tree from staying wet for long periods (too much water could cause it to rot).

Start planting by throwing a couple of shovels of soil (possibly mixed with some organic matter if the soil is poor – to help it hold moisture) into the bottom of the hole. Make this into a slight mound and then spread the roots out evenly over it. You then put some soil in the hole to anchor the tree in place and firm it down. Then re-fill the hole with the rest of the soil (make sure the tree remains vertical). You may also want to add some rock phosphate to the soil as you go.

When you have finished planting the tree should be on a slight mound, so as the soil settles it becomes flat. If it starts out flat it may end up as a slight depression where water can collect (which can be a problem on poorly drained soils).

You then water the tree thoroughly, not only to supply water to the plant, but also to settle the soil and establish contact between roots and soil.

The final step is to spread out a mulch to conserve water, and keep down weed competition (keep this six inches away from the trunk).

It is also a very good idea to put a permanent label on the tree saying the variety and rootstock (and write it down in your garden journal).

Support: Newly planted trees were once routinely supplied with a stake to support them, but it is now thought that trees become stronger more rapidly if not staked. Staking is only usually necessary on very windy sites (especially for dwarf trees which grow on weak rootstocks).

Protection: If gophers live in your area you will have to plant your trees in gopher wire baskets (I make my own to whatever size I need). If other rodents are a problem (they may chew on the bark, stunting or even killing the tree) you may have to use various kinds of metal or plastic mouse guards. These should go several inches into the ground and should have gravel around them to deter digging.

Maintenance: Apples aren’t usually very demanding plants, though a few pests and diseases can be troublesome in some areas.

Watering: Young trees need a regular supply of water to help them get established, so irrigate if necessary watering (I like to use a circle of in-line drip emitter tubing). Established trees are actually quite drought tolerant, but will be more productive with an occasional deep. Trees on the less vigorous dwarfing rootstocks need watering more than thos eon standards as their roots aren’t as strong.

Trees grown without irrigation may produce less and smaller fruit, but it may be sweeter and better flavored because they contain less water. I don’t water my older trees at all (they go without rain for up to five months) as they seem able to tap into groundwater.

Feeding: If your trees are putting on a reasonable amount of growth annually (at least 9-12” of growth) then they don’t need any additional feeding. Young plants don’t usually need any supplemental feeding either. However heavily producing trees can use a lot of nutrients and may benefit from a rich mulch of compost or aged manure.

If your trees aren’t growing well (less than 9” of growth) then you might want to feed them with a standard fertilizer mix to supply additional nitrogen, potassium and other nutrients. This is scattered around the tree out near the drip line. A rule of thumb says to use 1 lb 10-10-10 fertilizer the first year (in early spring), 2lb the next year, 3lb the year after, increasing by 1 lb every year up to 5lb.

A foliar feed of seaweed can also improve yields. Wood ashes are good too.

Weeding: Apple trees don’t grow well near grass because it competes for soil nutrients and moisture in the same part of the soil. The best way to control grass and other weeds around the trees is with mulch (hand pulling is good too). The worst way is with a string trimmer which will almost inevitably damage the bark and any drip irrigation lines (and only chops off the top part of the grass anyway).

Mulch: Is very helpful because it supplies nutrients, controls weeds and conserves soil moisture all at the same time. It should start 6” out from the trunk and go out to the drip-line. Don’t put it right up to the trunk as it may hold moisture and cause crown rot, or provide a hiding place for rodents who may eat the bark in spring. The mulch layer should be replenished annually in spring.

Training: The most important aspect of pruning is to encourage the tree to assume the desired shape, which means a strong framework of well spaced, wide angled branches. You also want light and air to be able to reach fruit in the center of the tree. The commonest way to do this is to prune to an open center or vase shape, (which apple trees tend to assume naturally). You can also train them to grow as a central leader.

Apples can be grown in small spaces by training them to grow flat against a wall, as fans, cordons, espaliers and more. These take up less space and can look quite spectacular, but the tradeoff is that they require a lot more work to train and maintain them, all for less fruit. They only really make sense if you want to grow fruit in limited space. If you place the trees against a south or west facing wall, they will get additional warmth, which can be important in cool climates.

Pruning: Once you have the tree trained to the desired shape, they are usually pruned annually. This is done to admit light, give good air circulation, thin out overly dense areas of foliage and to maintain a proportion of fruiting wood. You also remove diseased, crossed and spindly branches. It is sometimes said that a bird should be able to fly through the middle of a properly pruned tree!

Pruning can have a big effect on the vigor of a plant. Pruning while the tree is dormant in the winter stimulates vegetative growth. Pruning in summer while it is in leaf makes it less vigorous and slows it down. Hard pruning encourages vigorous vegetative growth, but reduces fruiting.

You don’t have to prune your apple trees, they will still produce as much weight of fruit if unpruned, but the individual apples will be smaller (unless vigorously thinned), they may be more prone to disease (due to crowding). The tree may also be poorly shaped, unless you allowed it to grow naturally right from the beginning (once you start pruning and upset the trees natural shape, you have to keep on doing it). If the tree grows very rapidly the overly long and slender branches may be weak and may break under the heavy load. The tree may also revert to biennial bearing.

When to prune: Apple trees are most often pruned while they are dormant. In mild climates this can be any time after they drop their leaves and go dormant, from late fall to early spring. In colder areas they are usually pruned in late winter or early spring (after danger of extreme cold is past). Trees are sometimes pruned in summer too, to reduce their vigor.

How to prune: How you prune for fruiting depends upon whether a tree is a spur bearer or a tip bearer.

Most apples are spur bearers and produce fruit on short stubby twigs (spurs) that are produced on branches that are at least two years old. These tend to bear more heavily than tip bearers.

Tip bearers produce fruit at the ends of the previous years growth (though they may also produce some on spurs). These don’t need as frequent pruning as spur bearers. Which ones

Pruning can follow a regular pattern:

• Remove any dead, diseased or broken branches.

• Remove suckers (shoots from roots) and watersprouts (vertical shoots).

• Remove any branches that for acute angle crotches.

• Remove crossed branches that touch or rub.

• Don’t remove more than a third of a tree in a single season. Always cut to just above a bud that faces the direction you want.

Pollination: Though apple flowers are complete (have both male and female parts) most varieties are self-infertile and so require cross-pollination by insects (mainly bees). This means you must have at least two different, but compatible, varieties and they must be planted close together (ideally within 50 ft). Of course they must also bloom at roughly the same time. Triploid varieties (Gravenstein, Bramley and others) produce sterile pollen and aren’t good pollinators. Apparently they also require pollen from two different varieties to produce fruit.

If you have limited room it is possible to graft a branch of a suitable pollinator onto a tree, or even have several varieties. There are also a few self-pollinated varieties Which ones.

Apples generally bloom fairly late so the flowers aren’t often damaged by frost.

Propagation: Apple varieties are propagated by grafting the scion on to a suitable rootstock. There are no good vegetative methods of propagation for apples.

Apples can easily be grown from seed, but the fruit the trees produce will vary enormously (apples are hybrids) and will usually be inferior to the parent trees (these can be used for rootstocks if you want a full sized tree). Of course some may produce good fruit and this is where all cultivars were produced originally.

If you want to try growing your own trees, sow the ripe seed in autumn in a protected place and it should germinate the following spring. You can also stratify the seed for 6-8 weeks at just above freezing (though it may take a year or more to germinate).

Fruit thinning; A newly planted tree shouldn’t be allowed to produce any fruit in its first two summers, so it can devote all of its energy to vegetative growth. Any fruit that appears should be removed promptly.

An established tree will often set more fruit than it can really handle and this should be thinned out conscientiously. This is done to improve the size and quality of the fruit, prevent limbs breaking, and to discourage biennial bearing (if you allow a tree to produce too much fruit one year, it may not produce any the following year).

Thinning should be done fairly early (while the fruit is less than 1” in diameter) to avoid wasting the trees energy. Don’t thin too early though, as some fruit will fall off naturally (this is known as June drop). How much fruit you allow a tree to produce will depend upon its size and condition. If branches are sagging significantly it has too much fruit and should have been thinned more.

How to thin: Apple blossom occurs in clusters of up to 6 individual flowers and all may set fruit. These clusters should be thinned to leave just one fruitlet (or sometimes two) at each node, so fruit is spaced 4 to 6 inches apart (6-9 for large cooking apples) along the branch. This results in the best and largest fruit and ensures the tree has enough energy to do the same again next year. When you thin a fruit cluster you should leaves the biggest and best fruitlet on the tree and remove any misshapen, damaged or otherwise inferior ones (you can remove these even before the June drop).

Support; In a good year the branches may become so heavily laden with fruit, that there is a chance they might break under their own weight. You don’t want this to happen as it will spoil the shape of the tree and maybe allow infection to enter through wounds (you also lose the fruit of course). Avoid this by supporting the straining branches with wooden props. These are usually long poles with a fork at the end, which is padded in some way to prevent damage to the branch. You can also have one tall pole and tie all of the branches to it. Of course the best way to avoid having to do this is to thin the fruit properly beforehand.

Pests: Apples are vulnerable to attack from a number of pests and diseases, especially when growing in less than ideal circumstances. Good sanitation is very important in this regard, so clean up fallen apples and leaves and remove any diseased or infected branches. In many areas even organic gardeners often have to resort to a regular program of spraying to keep problems under control.

If all of these pests were dealt with in a separate section I wouldn’t have to keep repeating them.

Scale

Apple maggot (Rhagoletis pomonella) These are the larvae of a small fly and shouldn’t be confused with Codling Moth. They are small (1/4”) and make a series of small tunnels in the fruit.

Fruitworms

Plum curculios

Leafhoppers

Mites

Aphids: These are a common problem, and in sufficient numbers they can cause growing tips to wither and die. The simplest remedy is to spray them off the plant with a strong jet of water. You might also band the trunk to prevent ants herding them in the trees. 

Codling moth: This is a serious problem in many areas and is commonly responsible for the worms you occasionally find in apples. In some commercial fruit growing areas you are required by law to control them! Always remove fruit debris from under trees where they can over winter.

Birds and wasps – These will often attack fruit, either individually or wasps will come in after the birds have pecked holes in the fruit. You could try netting the whole tree to keep birds off, but it’s easier to simply enclose each individual fruit in a waxed paper bag. As an added benefit this can produce perfect fruit.

Diseases

Several diseases can be problematic and if one is particularly bad in your area it really helps to choose resistant varieties. You should also prune to give good sun and air circulation and to remove diseased parts. Also use good sanitation, removing any dead leaves and dropped fruit that could be a source of infection.

Cedar Apple Rust

Canker

Powdery mildew

Fire blight Can be serious in some areas.

Scab – This manifests itself as brown lesions on leaves (these eventually drop off) and fruit and is a common problem in areas with wet spring weather. Some varieties are resistant and you can spray with sulphur. Fortunately this is a disease you can often ignore as the damage is usually cosmetic).

Biennial bearing: When a tree bears a large crop every alternate year and almost nothing in between, it is said to be biennial bearing. This usually occurs when a tree is overloaded with fruit one year (often combined with water stress or poor fertility) and so doesn’t produce fruit buds at the same time. It then needs a year to recover and produce new fruit buds. Some varieties are prone to this? The best way to avoid it is to thin and prune carefully so it doesn’t produce too much fruit in any one year.

Of course if you always have lots of fruit on other trees then biennial bearing may not be a problem.

Unusual growing ideas:

Family trees: You can graft several varieties on to one tree, to get good pollination and an extended harvest season. The varieties have to be compatible and grow at roughly the same rates.

Landscape uses: The white blossoms are tinged with pink and make the plant a spectacular ornamental in spring. The fruit can also be pretty.

Harvest

The fruit matures in anywhere from 100 – 200 days, depending upon the variety (not surprisingly northern varieties tend to be earlier, while southern ones take longer). The earliest types might ripen as early as July, while the latest varieties may take until November. Obviously it’s hard to predict exactly when they will reach maturity because it depends upon the weather (when winter ended, how warm it’s been). If you have the room you can plant several varieties, with different maturation dates and have fresh apples for many months. Careful storage can extend this even further.

The apples on a tree won’t all ripen at once, those in sun will usually be first, while very shaded fruit will be last. You will soon learn when a fruit is ripe and ready for eating. Apples for eating immediately should be fully ripe, which means they will separate from the tree if lifted and twisted ever so slightly. The skin will change from a uniform green to yellow, red or a variety of shades in between. The seeds of a ripe fruit will be blackish rather than white, and the flesh will become whiter and softer as it ripens. Of course it will also start to taste sweet and good (if it tastes good it is ready).

When apples start to fall it is a good indicator that they are ripe (though they may also fall after being damaged, or be knocked off by birds or animals). When picking an apple the stalk should remain on the fruit.

Dessert apples shouldn’t stay on the tree too long, or they will deteriorate. This applies particularly to the early varieties, which are often picked just before fully ripe. Apples for storage are also often picked when slightly unripe. Late apples mature further off the tree and can take several weeks to reach their peak flavor.

Cider or juice apples are often left to fall from the tree on their own and gathered from the ground. They don’t need to be perfect as no one will see them.

Storage: Apples can be stored in a cool humid place for weeks (or even months), so long as they are completely free of bruises or blemishes (they should also be picked slightly unripe). Small quantities can be stored in perforated plastic bags (to retain humidity, but allow them to breathe) in the fridge (or in the vegetable drawer). A storage area for larger quantities should be well ventilated, a cool 35-40°F and have some humidity.

Apples can also be made into apple sauce, sliced and frozen or dried.

Food uses: The fruit is rich in pectin and can be added to other fruits when making jam to help them set.

Rootstocks

Commercial apple trees are pretty much all grafted and consist of a scion and a rootstock which grow together to form one plant. The scion is the top part of the tree and will be the variety you chose. The rootstock (the lower part of course) used to be a seedling, but now it is usually a dwarfing rootstock of some kind. These affect the eventual size of plants by their vigor (a less efficient and vigorous rootstock will produce a smaller tree) and can dwarf a tree by as much as 90%.

Not only are there hundred of varieties of Apple, there are also many different rootstocks. These determine the eventual size of the tree and give you great flexibility in planning your edible garden, by enabling you to grow apples in a variety of shapes and sizes, ranging from standard trees down to dwarfs, fans and stopovers (which as the name suggests are low enough to actually step over).

Apples were the first fruits to be grown on dwarfing rootstocks and are now available in a range of sizes to fit any garden. The rootstock doesn’t just control the eventual size of the tree, but also enables it to bear at an earlier age and may also improve resistance to pest, disease and adverse growing conditions. The rootstock doesn’t have any effect on the flavor of the fruit, which is decided solely by the scion.

Dwarf trees: These are usually under 10ft high when full grown (they include M9, M26 and M27) are useful for small gardens (or even containers). However their roots are weak and so the trees need rich soil and careful maintenance (they can’t compete with grass either). The small trees are easy to prune and pick and though production from each individual tree is limited, you can get several trees in the space of one full size tree. They are spaced 8-10ft apart and can yield from 40-60lb of fruit annually.

Semi-dwarf trees (M7, MM106) grow into intermediate size trees 12-18ft tall and should be spaced 15-20ft apart. They require a moderately large garden and can tolerate planting in grass. They start bearing in 3-5 years (depending on variety, climate and individual rootstock).and can produce 70-90lb of fruit annually.

Standard trees (MM111, M2) can grow up to 40 ft in height, but may be kept smaller by pruning. They are very vigorous and are only suitable for large gardens. They may be planted 20-30ft apart. They can be used as the canopy layer of a forest garden, but of course it may be hard to harvest fruit if the tree is so tall. They may take 5 years or more to start bearing. and yield 60-120lb of fruit annually. Because they are so large they are hard to prune and pick (a pole picker works well).

Common rootstocks include:

Antonovka: 25-30 feet Cold hardy (also produces good fruit itself)

MM 111: (65-85%) 20ft tall x 20ft wide. Vigorous, most soils, tolerates heavy soil. Starts bearing in 4-6 yrs, Fireblight and drought resistant.

M 25: 25ft tall x 20ft wide. Vigorous.

MM 106: (45-65%) 15-180ft tall x 15ft wide. Precocious, heavy bearing, tolerates wet heavy soil. Starts bearing in 3-4 yrs

M7A: (50-60%) 15ft precocious Starts bearing in 3-4 yrs

M.9: (25- 35%).

M 26: (30-40%) 12ft tall x 12ft wide. Semi dwarf, precocious, hardy, heavy bearing, well drained soil, shallow roots. Starts bearing in 2-3 yrs

M27: (15%) 4-6ft Very precocious. Starts bearing in 2-3 yrs. Works well in containers

Seedling: (any seed) 30ft Vigorous, slow to bear, taking 6-10 yrs.

Varieties: There are literally thousands of Apple varieties in existence, but only a few are readily available. If you want some of the rarer varieties there are a number of nurseries that specialize in them (just look online). There are several factors to take account when choose suitable varieties for your garden:

In my opinion the most obvious (and important) is flavor, if you are going to all of the trouble to plant and tend a tree (which takes up space in your garden) then you should make sure it is of exceptional quality and flavor.

Almost as important as flavor, is choosing a variety that will do well in your climate, taking into account humidity, heat and chill requirements and more.

You will also want to consider when you want to harvest the fruit (ideally you will choose several trees that fruit in succession), pollination compatibility (some varieties don’t produce viable pollen or produce at different times) and disease resistance (this can be very important in some situations). You will also want the trees to grow to a certain size, so the rootstock is also a consideration.

Triploid varieties tend to be very vigorous and aren’t usually grown as espaliers or other restricted forms. They are hybrids and produce sterile seeds. They also require two pollenizers.

Don’t forget you will need to plant at least two compatible trees to ensure good pollination, unless you use one of the few self-fertile varieties (these include Golden Delicious???  and Queen Cox).