A fruit rootstock is a stump of an established related species grafted onto to a separate fruit tree. These are identifiable by a bulge a few inches from the bottom of the stem where the wood has knitted together.
This is done for multiple reasons, including controlling the height of the tree, improving disease resilience, and allowing the cultivation of trees in a smaller space then if grown on its own. But it is worth remembering that the rootstock has no influence over the size of the fruit itself.
Rootstock we use:
|Fruit Type||Rootstock Name||Rootstock Type||Ultimate Height||Start Fruiting||Growing Conditions||Spacing|
|Apple||MM106||Semi-dwarfing||3-5 m||3 – 4 years||Range of soils including grassed orchards and poor soils||3.6 m (12ft) with 4.5m (15ft) between rows|
|Plum||St Julien A||Semi Vigorous||2 m||3 – 4 years||Heavy soils are tolerated||5m (18ft)|
|Peach||St Julien A||Semi Vigorous||2 m||3 – 4 years||Heavy soils are tolerated||5m (18ft)|
|Cherry||Colt||Semi Vigorous||2 m||3 – 4 years||Many soils tolerated including clay and light, chalky soils||6m (20ft)|
|Pear||Quince A||Semi Vigorous||2 m||After 4 years||Medium to heavy fertile soils||3 – 4.5m (10 – 15ft)|
Rootstock Names Explained
In 1977, Colt was made at the East Malling Research Station in Kent. It is a cross between a related but less vigorous species of sweet cherry, Prunus Pseudocerasus and the sweet cherry Prunus Avium. It was the first sweet cherry dwarfing rootstock, allowing a cherry tree to be grown in a small garden.
In Europe, this is probably the most adaptable rootstock for cultivating specimen apple trees. Additionally, it is the best method for creating large, trained forms like espaliers. Once established, trees on MM106 will tolerate other plants or grass growing around them and only require occasional watering during dry spells. While most of the crop should be accessible from the ground, picking fruit from higher up on the tree may require a ladder.
Quince A (not Quince Adams) is a widely planted semi-vigorous pear rootstock. Pears grafted with Quince A often grow to a height of 3 – 4m after 5-10 years. Often considered equivalent to the apple MM106 but is less vigorous, they do best in good soils but is not tolerant of chalk or drought conditions.
A semi-vigorous rootstock that produces trees about the same size as the apple MM106 rootstock. St. Juliens were originally grown for their fruit, which is useful for drying but not particularly eating. A tree grown on St. Julien rootstocks is significantly smaller than a tree grown on its own roots. After three to four years, plum trees typically bear fruit. With some tolerance for chalky soils, St. Julien can thrive in a wide range of soil types.