In order to contain their rate of growth, fruit trees are grown on a range of rootstocks. Please click on the following “rootstocks explained” link to view a diagram showing the potential height of mature trees grown on a variety of rootstocks:
To illustrate the effect of rootstock, the following image shows the difference between two untrained cherries of the same age. The tree on the left is grown on Gisela 5 root stock, while the tree on the right is grown on the more vigorous Colt rootstock: