How to Grow Apple Trees: Rootstock and Pollination First

Two things decided at the moment of purchase determine almost everything about an apple tree: what rootstock it is grafted onto, and whether something nearby will pollinate it.

Both are printed on the label, both are routinely ignored, and neither can be changed afterwards.

Rootstock: the decision that sets the tree

An apple tree is two plants — a variety grafted onto a root system chosen for size control. The variety decides the fruit; the rootstock decides the tree.

M26 or MM106 is right for most gardens — large enough to support itself once established, small enough to prune and pick without a ladder.

M27 and M9 need a stake for life. Their roots are genuinely too weak to hold the tree in wind, and an unstaked dwarf will lean and eventually go over carrying a crop. This is not optional.

Pollination

Most apples are self-incompatible: they cannot set fruit with their own pollen and need a different variety flowering at the same time.

Varieties are sorted into flowering groups, numbered 1 to 7, from earliest to latest. A partner must be in the same group or one adjacent — so a group 3 tree is pollinated by groups 2, 3 or 4.

Three complications worth knowing:

• Triploid varieties — Bramley, Blenheim Orange, Jonagold — produce sterile pollen. They need two other compatible varieties, which then pollinate each other as well.
• “Self-fertile” varieties — Braeburn, Falstaff, Red Windsor — do set some fruit alone, but crop considerably better with a partner.
• You may not need to plant one. Bees travel, and a neighbour’s apple tree, a nearby crabapple, or anything in an adjacent garden within a few hundred feet will do the work. A crabapple is the efficient answer in a small garden: it flowers over a long period and pollinates almost everything.

Choosing a variety

Beyond flowering group, the things that actually matter:

• Purpose — dessert, cooking, cider, or dual-purpose.
• Disease resistance, especially to scab and canker, which are the two that ruin apples in wet climates. This matters more than flavour notes in a damp garden.
• Storage — early varieties are eaten within days; late ones keep for months.
• Local suitability. Old regional varieties exist because they worked in that climate.

There are over 7,500 named apple cultivars, so the choice is not the constraint. Buying from a specialist nursery that will tell you the rootstock and flowering group is.

Planting

Bare-root, in winter dormancy, is cheaper and establishes better than a container tree. Container trees can go in year round but need more watering.

1. Full sun, shelter from wind, free-draining soil. Avoid frost pockets — late frost on blossom is the commonest cause of a lost crop.
2. Dig a hole twice the root spread and no deeper than the roots. Do not dig a deep hole and backfill; the tree settles and the graft union sinks.
3. Drive the stake in first, before the tree goes in, so it does not spear the roots. A short stake angled at 45 degrees, or a vertical one to about a third of the tree’s height.
4. Position the graft union at least 4 inches above the finished level.
5. Backfill with the soil you dug out. Do not enrich the hole — it encourages roots to circle rather than spread.
6. Tie loosely, firm, water in well, and mulch in a ring clear of the trunk.
7. Keep a 3-foot circle grass-free for the first few years. Grass competes hard with a young tree.

Pruning

Winter, while dormant, for a normal free-standing tree. You can see the structure, and the tree responds with vigour.

The aim is an open goblet: a clear trunk, three to five main branches, and an open centre so light and air reach the fruit.

• Remove dead, damaged and diseased wood first.
• Remove crossing and rubbing branches.
• Remove anything growing inward across the centre.
• Take out water shoots — vertical whips — and any growth from below the graft, which is rootstock and will take over if allowed.
• Never remove more than about a quarter of the canopy in one winter. Hard pruning provokes a mass of unproductive vertical regrowth.

Summer pruning is for trained forms — espaliers, cordons, fans — where the point is to restrict growth and force fruit buds rather than stimulate new wood.

Never prune in autumn. Wounds heal slowly and canker spores are at their most abundant.

Thinning, and biennial bearing

An apple tree that sets a very heavy crop exhausts itself and produces little or nothing the following year. Once that rhythm starts it tends to persist.

Thin the fruitlets in early summer, after the natural “June drop”. Leave one or two fruits per cluster, spaced roughly 4 to 6 inches apart. You lose count and gain size, flavour, and a crop next year too.

Common problems

Scab — olive-brown blotches on leaves and corky patches on fruit. Rake up fallen leaves; choose resistant varieties.

Canker — sunken, cracked patches on bark, often at a pruning wound. Cut out well below the damage and burn it.

Codling moth — maggots in the core. Pheromone traps from late spring.

Woolly aphid — white fluffy patches on bark. Encourage predators; scrub small infestations off.

No fruit despite flowers — pollination, frost, biennial bearing, or too much nitrogen from lawn feed applied nearby.

And if you were thinking of starting from a pip — read growing an apple tree from seed first, because the result is not the apple you ate.