Apple root stocks

Rootstocks Pollination for successful fruiting
Fruit trees are grown on rootstocks which determine vigour and eventual size. Each type has different characteristics. Pollination Groups (GRP): Apple trees require a pollination partner growing nearby, either a fruiting or an ornamental apple tree, that flowers at a similar time. A few varieties are Triploid(T) and require two pollination partners. These are indicated in the table.The flowering period, which ranges from A (early) to E (late), is given in the apple varieties table. A variety can be pollinated by another of the same flowering period or one to either side.

Explanation of Terms
Maidens – one year trees 1m – 2m (3-4ft) tall. Depending on variety may or may not have branching.

Bush – two year trees topped at 75cm to produce a head of branches.

Container – tree in a ten-litre pot topped at 75cm to produce a bush tree.

MM106
for most situations and forms. Will reach 4-5m (12-15ft) Most apple varieties are available on this rootstock.
M111
Similar to MM106 but more vigorous, up to 4.5-5.5m (15-18ft).
M25
Vigorous, reaching 5-6.5m (15′-20′). Suitable for standards.
M26
Semi dwarfing, reaching 2.5-3.5m (8-10ft). Ideal for smaller gardens. A few varieties available on this rootstock.
M9
Dwarfing, to 2-2.5m (7-8ft).Good soil and staking required.