Apple tree

Malus domestica

FruitFamily: Rosaceae (Rosacées)Difficulty: Medium

The apple tree (Malus domestica) is the king of fruit trees in the Belgian climate, the one that has filled the orchards of the Herve region for generations. It enjoys our mild summers and cool winters, which give it exactly the cold its buds need to flower in spring. Two things decide success: the rootstock, which sets the final size of the tree, and the presence of a second compatible variety nearby, since most apple trees only fruit well with cross-pollination. Under our damp skies, the real battle is fought against scab, which stains leaves and fruit as soon as the spring turns rainy.

Light and exposure

The apple tree wants sun to ripen its fruit and concentrate the sugar. Give it an open, sunny spot with at least six hours of direct light a day. In a shady garden the tree still grows, but the harvest stays meagre and the fruit tastes bland.

An airy position where the air circulates well is worth its weight in gold under our climate: the foliage dries faster after rain and scab settles in less easily. Avoid valley bottoms where cold air pools and where spring frosts linger longer during flowering.

Watering

An apple tree well rooted in open ground manages on its own most years here, since Belgian rainfall covers its needs. During the first two or three years after planting, however, water generously in case of summer drought so the root system establishes itself deeply.

Keep a special eye on young trees and espaliered forms on dwarfing rootstock, whose roots stay shallow and quickly suffer from dryness. A mulch at the base keeps the soil cool and saves you from watering all the time. In a hot, dry summer, a lack of water while the fruit is swelling means smaller apples.

Soil and repotting

The apple tree accepts most of our soils, but prefers a deep, cool, well-drained earth, neither too chalky nor permanently waterlogged. The heavy clay soils of the Herve plateau suit it fine, as long as water does not sit around the roots in winter.

At planting, dig a wide hole, loosen the bottom and work in mature compost without burying the graft point, which must stay well above the soil. Ground that is too soggy encourages root rot and root suffocation: on wet land, plant on a small mound to raise the collar.

Temperature and humidity

The apple tree is perfectly hardy in Belgium and does not fear our winters, even harsh ones. It actually needs a certain number of chill hours each winter to break the dormancy of its buds and flower properly in spring, a need our climate meets without difficulty.

The sensitive point is flowering. The apple tree flowers fairly late, often in late April or in May, which partly protects it from the last frosts. But a night of frost during full bloom scorches the flowers and ruins the year’s harvest. In cold hollows, a late frost at that moment makes all the difference between a fine year and a blank season.

Pruning and upkeep

Formative pruning is done in the first years, in winter and out of frost, to build a balanced, airy framework. You open the centre of the tree to the light and keep well-spaced branches. On a standard orchard tree you let it spread; on an espalier or goblet form you guide each branch.

Maintenance pruning, also in winter, removes dead wood, crossing branches and surplus watershoots, while renewing the fruiting spurs. Summer pruning is possible: you pinch or shorten the year’s growth, which calms vigour, lets sun onto the fruit and encourages fruit buds for next year. There is no point pruning an over-vigorous tree hard, it simply responds by growing back stronger.

Pests and diseases

The number one enemy under our damp climate is scab, a fungus that covers the leaves with olive-brown spots and marks the fruit with black corky scabs. It explodes during rainy springs, when the foliage stays wet for a long time. The best defence is to choose resistant varieties from the start, often old local varieties suited to our orchards, and to rake up and remove the fallen leaves in autumn, where the fungus overwinters.

Codling moth, the famous apple worm, tunnels through the fruit: pheromone traps and trap bands around the trunk help to keep it in check. Watch out too for aphids, which curl up the young shoots in spring, and powdery mildew, that white felting on young leaves and shoots in mild weather. Cut and burn affected shoots, and encourage helpers like ladybirds rather than spraying at random.

Propagation

The apple tree does not come true from seed: a pip gives an unknown tree, rarely good to eat. To get a specific variety, you propagate it by grafting onto a chosen rootstock. It is the rootstock that decides the final size: a dwarfing rootstock gives a small tree for a little garden or an espalier, a seedling stock gives a vigorous standard for a full orchard.

Grafting is done by budding at the end of summer, or by cleft and whip-and-tongue in spring on a rootstock planted the previous winter. It is a technical but accessible gesture, very rewarding when you want to save an old local variety. For the gardener in a hurry, buying a grafted maiden from a nursery is the simplest route: you then choose the variety and the rootstock in one go.

Local know-how

In Belgium (Herve climate, zone 8a)

The apple tree is at home in the Herve region, to the point of having shaped the landscape with its standard-tree meadow orchards. Hardy and comfortable in our winters, it mainly raises two questions at planting time. First the variety and its companion: most apple trees need a second compatible variety that flowers at the same time, in the garden or next door, so the bees can carry out cross-pollination and therefore set fruit. Then the rootstock, which controls the size: dwarfing for a small garden, a cordon or an espalier against a wall, a seedling stock if you dream of an old-fashioned standard.

The Belgian calendar revolves around flowering, often in late April or in May. That is when the risk of a late frost looms, especially in cold hollows: a night of frost on the open flowers can cost the harvest. The rest of the year, everything comes down to fighting the scab that our rainy springs love. Betting on resistant old local varieties, pruning to open up the tree, raking up the fallen leaves in autumn, these are the gestures that make the difference here. The harvest spreads from late summer into autumn depending on the variety, from early August apples to late-autumn keeping apples that store all winter in a cool cellar.

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Month-by-month care calendar

JanuaryPeak season for bare-root planting, out of frost. Formative and maintenance pruning of established trees, in dry, mild weather.
FebruaryEnd of the ideal window for planting and winter pruning. Apply a clay wash to the trunks if you wish. Check and set the stakes.
MarchBud break approaching. Last moment to prune before the sap rises. Clean around the base of the trees and mulch young specimens.
AprilFlowering begins. Watch for forecast late frosts and protect young trees in bloom on cold nights. Look out for the first aphids.
MayFull bloom then fruit set. The bees do their work of cross-pollination. Watch for scab if the weather is rainy and humid.
JunePhysiological drop of young fruit, quite normal. Thin by hand if the tree is overloaded for finer fruit. Set the codling moth traps.
JulySummer pruning possible on espaliered forms and over-vigorous trees. Water young trees in case of drought. Watch for codling moth and powdery mildew.
AugustFirst early apples to pick and eat quickly. End of summer pruning. Keep watering young specimens if the summer is dry.
SeptemberFull harvest of the main-season varieties. Pick gently, the fruit should come away with a light twist. Gather the fallen fruit.
OctoberHarvest of the keeping apples, to bring into a cool cellar for winter. Rake up and remove the leaves affected by scab.
NovemberLeaf fall, the tree enters its rest. A good time to plant bare-root. Clean under the trees to break the disease cycle.
DecemberVegetative rest. Plan your planting and the choice of mutually compatible varieties. Winter pruning can begin in mild, frost-free weather.

Green Hub tips

  • Always plant at least two compatible varieties that flower at the same time, or check that an apple tree already grows at a close neighbour’s: without cross-pollination, many varieties give little or no fruit.
  • Choose the rootstock according to the space: dwarfing for a small garden or an espalier against a wall, seedling stock for a full-orchard standard that will live for decades.
  • Under our damp climate, bet on old local varieties resistant to scab, far easier to grow than supermarket varieties.
  • Rake up and remove the dead leaves in autumn: that is where scab overwinters, and a clean base breaks the cycle for the following year.
  • Do not pick a keeping apple too early: it should come away easily with a light twist of the hand, otherwise it will shrivel in the cellar.