Rootstocks & shapes

Rootstocks and tree shapes

The label says ‘Cox’. The small print says M26. The small print decides whether you get a patio tree or something to hang a swing from.

What a rootstock does

Apple trees are sold as two plants joined together: a rootstock, which controls the tree’s size, and a cultivar, which forms the top. RHS: Stepover training

From tiny to huge

Apple rootstocks, from the smallest to the biggest tree (grown as a bush)
Rootstock	Vigour	Tree height	Starts fruiting	Source
M27	extremely dwarfing	1.2–1.8m	after two years	RHS: Fruit tree rootstocks
M9	dwarfing	1.8–2.4m	after two or three years	RHS: Fruit tree rootstocks
M26	dwarfing	2.4–3m	after two or three years	RHS: Fruit tree rootstocks
MM106	semi-dwarfing	3–4m	after three or four years	RHS: Fruit tree rootstocks
MM111	vigorous	4–4.5m	after four or five years	RHS: Fruit tree rootstocks
M25	very vigorous	over 4.5m	after five or six years	RHS: Fruit tree rootstocks

MM106 is semi-dwarfing: it starts fruiting after three or four years and makes a tree about 3–4m (10–13ft) tall. It’s the most widely used rootstock, but too big for small gardens. RHS: Fruit tree rootstocks

For small gardens, pots and cordons, the RHS suggests a dwarfing rootstock such as M9 or M26. RHS: How to grow apples

Try it: Rootstock Picker →

Bush, half-standard or standard?

A bush tree has a clear trunk of about 75cm (30in) before the branches start; a half-standard about 1.35m, and a standard about 2m. RHS: Choosing the best fruit trees

Trained shapes for small spaces

Cordons

A cordon is restricted by pruning to one main stem, upright or at 45°, with short fruiting side-shoots called spurs. RHS: How to grow apples

Espaliers

An espalier is trained flat against a wall or fence, with a central stem and tiers of horizontal arms. Most have three or four tiers and reach about 1.8m tall and 3–4.5m wide. RHS: Training an espalier

Established espaliers need pruning every year in late summer, or they slowly turn back into ordinary trees. RHS: Training an espalier

A fruit tree trained flat against a wall, its branches running out sideways in level tiers — A horizontal espalier on a test site for fruit tree forms near the castle of Gaasbeek (KVDP).Photo: KVDP, Public domain, Commons

Stepovers

A stepover is a tiny tree with a short trunk, usually 45–60cm tall, and one or two arms trained sideways to make a T-shape, low enough to step over. RHS: Stepover training The two arms of a T-shaped stepover can stretch to 3–3.5m in total. RHS: Stepover training

M27 is the best rootstock for a stepover; M9 is useful for stepovers on poor soil. RHS: Stepover training

Tip-bearing apples, which fruit at the ends of their shoots, aren’t suitable for stepovers. RHS: Stepover training

In a pot

For a pot, choose an M9 or M26 tree and a container at least 45cm (18in) across, filled with John Innes No 3 compost. RHS: How to grow apples

Next: planting and care →