To those that are new to growing their own fruit, the concept of rootstocks can seem a little daunting. However, it's not as complicated as it seems!
Read on for everything you need to know about fruit tree rootstocks, including what they are, what they do, and how to choose the right one for you. We've also put together a handy table containing some of the most common rootstocks specific to each type of fruit.
What's in this guide
What is a rootstock?
All of our fruit trees are grafted (or joined) onto rootstocks.
A rootstock is essentially the stump of a similar species with an established root system. When we say that a fruit tree has been grafted onto a rootstock, what this means is that the fruit tree in question has a root system from another tree.
If you look towards the bottom of the trunk of your fruit tree, you can normally see a bulge or a kink where the grafting has taken place.
What do rootstocks do?
A rootstock simply determines how vigorous a fruit tree is, and therefore how big it will get.
Fruit trees grown naturally can reach heights in excess of 4.5 metres which are impractical for most gardens and make harvesting difficult. Rootstocks meanwhile allow us to control the final height of a fruit tree. If you take the root system from a naturally compact (or less vigorous) species, for instance, and graft a fruit tree onto it, the fruit tree will adopt that species' compact size.
A more vigorous rootstock is ideal if you have more space and would like a large fruit tree. A semi-vigorous rootstock or a dwarf rootstock help keep the tree to a smaller, more manageable size, so are best for smaller gardens and growing in pots. The names of rootstocks differ by fruit species – see our table below for more on this.
Rootstocks also offer other advantages. Trees grown on rootstocks will produce fruit faster than trees grown from seed. They are also hardier and generally have a better resistance to diseases. The size of the fruit produced is unaffected by rootstocks – it will be the same regardless of whether your tree has a more vigorous or less vigorous rootstock.
Table showing rootstock types and sizes
How to choose a rootstock
Generally, you just need to choose the rootstock that corresponds to the height you would like your tree to reach.
Semi-vigorous, which is the most common, is an excellent general purpose rootstock ideal for various planting situations including espaliers and fan-trained trees.
If you're planting your fruit tree into a pot, or if you only have a small amount of space, anything between very dwarf and semi-vigorous is ideal.
For traditional orchards and very large gardens, vigorous and fully vigorous rootstocks are a good choice.
There are other factors that can affect the size of a fruit tree — we go into this below.
Other factors that affect the size of a fruit tree
Rootstocks are the main factor, but there are other things that can affect the overall size of a fruit tree which are worth bearing in mind.
Vigour of the chosen variety: Some varieties are more or less vigorous than others when grafted onto the same rootstock.
Soil conditions: Less than ideal soil conditions can reduce growth. Please note that all fruits trees will not do well on poor, shallow soils.
Geography: Where you are in the country, latitude and altitude. Fruit trees grown in northern exposed areas on poor soils will always be less vigorous than those grown in more favourable areas.
Pruning regime/training method: In a set time, trees pruned or trained will not reach the same size as those free growing.
