Rootstock Types & Habits (Apple)

Very Dwarfing

6ft /2m

Dwarfing

8ft/2.5m

Semi Dwarfing

10ft / 3m

Semi Vigorous

14ft/4m

Vigorous

18ft / 5m

M27

others available

M9

others available

M26

others available

M106

others available

MM111

others available

The most widely-used rootstock in Europe in the 19th century was called Paradise. During the 1920s researchers at East Malling Research Station in the UK were the first to classify rootstocks and develop new ones for specific purposes. One of their first rootstocks was "M9", which was developed from Paradise and another variety called "Jaune de Metz". (It is possible that "Jaune" refers to the golden yellow bark of this rootstock). Apple trees grown on M9 rootstocks are small, and they fruit very early in life - making this an ideal rootstock for commercial apple orchards, and it is indeed probably the most widely-planted of all rootstocks. East Malling Research Station, in conjunction with some other UK research stations at Merton and Long Ashton developed a range of virus-free rootstocks of which M27, M9, M26, MM106, M7, MM111, and M25 are in widespread use today. Note that the numbers in the East Malling series have no relation to the size of the tree - M27 and M26 produce trees which are respectively smaller and larger than M9!

The examples listed above are of the most popular UK  apple rootstocks which are well-known, smallest (1) to largest (5)

here is a little more general information about them:

M27

Very small indeed; around half the size of M9. Tree needs full support. Fruit size reduced slightly. Moribund in wet soils. Very little pruning is required once the tree is full size (around 5ft high; produces perhaps 20 apples a year). It's OK in pots. It's susceptible to tomato ring spot virus.

M9

The best known dwarfing rootstock. This is the rootstock used at Brogdale, UK, for the National Fruit Collection. It is a cross between a French tree, "Jaune de Metz", and the "Paradise" apple of ancient Persia. It is known as the "Paradise" stock of Europe. It fruits when very young, is fairly hardy, tolerant of wet but not drought, and compatible with all apple scions. It has to be staked strongly, its roots are slightly brittle, and it is about 8-9 feet tall at maturity on an ideal soil.

M26

A cross of M9 and M16. Used in irrigated orchards on well drained solis. Fruits early in its life, needs permanent staking, hardy. Susceptible to crown rot and fireblight. M26 is not so good in wet, clay soils where it is rather moribund. Produces burr knots - the beginnings of little aerial roots - which attract pests and which can compromise the tree; these can be sliced off carefully in the garden situation. Planting deeper (so less rootstock is exposed) helps solve the problem commercially. Reaches about 8-10ft if unpruned. OK in pots.

MM106

A hydbid of Northern Spy (English dessert apple) and English Broadleaf. Well anchored, fruits early in its life, few suckers, fruit matures late, trees have a long season, OK in pots with less vigorous varieties. Susceptible to crown and root rot. Recommended by my supplier as a substitute for M26 in wet, cold soil : a little more vigorous. Semidwarf. 9-11ft high. Resistant to woolly aphid.

M7

Descended from a French tree, "Doucin Reinette". Very hardy. Likes deep, well drained soils. It suckers badly, is prone to crown gall, is resistant to fireblight, and tolerates wet soils. About the same size as MM106 (semidwarf). Has been used in New Hampshire, USA for 40 years. Fruits in 5th year. Has a tendency to lean. Most trees are very fruitful. Needs staking for first 4-5 years.

MM111

Northern Spy hybrid. About 75% of full size; too large for small gardens. Prone to burr knots. 10-12ft. Semi-dwarfing or half-standard. Resistant to woolly aphid.

M2

Very similar in size and vigour to MM111. Not quite so vigorous as M25.

M25

Full size tree; avoid unless you have a large space in which to grow it. Very vigorous; typically 12-15ft high; can be bigger depending on variety, large, heavy, spreading tree.