By grafting a fruiting variety (the scion) on to a compatible rootstock, it is possible to reduce the mature size of the resulting tree. The extent of the size control is typically given as a percentage of the full-size or 'standard' tree.
The definition of a standard tree is not precise but is essentially a tree grown on its own roots without any rootstock influence. In practice a standard apple / cherry / pear / plum tree is likely to reach a height and spread of 5m-6m when planted in good conditions (apples perhaps a bit less, plums, pears, and cherries perhaps a bit more).
A dwarf apple tree is therefore likely to have an overall size of about a quarter of the standard tree, in terms of its overall canopy volume. The way in which the tree is trained will also have a considerable influence (for example most dwarf apple trees in commercial orchards will be trained to a height of 3m, which is well over 50% of a standard apple tree … but with very little side growth).
The following matrix shows the rootstocks used for each species by size class.
| Dwarf 25% |
Semi-dwarf 40% - 50% |
Semi-vigorous 60% - 80% |
Full size 90% - 100% |
|
|---|---|---|---|---|
| Almond | Krymsk 86 St. Julien |
|||
| Apple | M27 (15%) M9 |
M26 Interstems |
M116 MM106 MM111 Own-root |
M25 Malus seedling |
| Apricot | Krymsk 86 Torinel |
|||
| Cherry | Gisela 5 | Gisela 6 Krymsk 5 Colt |
F12/1 Prunus avium |
|
| Damson | VVA-1 Pixy |
St. Julien | Brompton | |
| Medlar | Quince A | Crataegus | ||
| Mirabelle | VVA-1 Pixy |
St. Julien Jaspi |
||
| Pear | Quince C Quince Eline |
Quince A BA29 Pyrodwarf |
Pyrus communis Pyrus Kirchensaller |
|
| Peach / Nectarine | Krymsk 86 St. Julien |
|||
| Plum | VVA-1 Pixy |
Wavit St. Julien Torinel Jaspi Krymsk 86 |
||
| Quince | Quince C | Quince A | ||
| Walnut | Juglans nigra |