This is a term used in the propagation technique of grafting. The basis of grafting is to attach a ‘rootstock’ of one plant (which includes the roots) to a ‘scion‘ of another (which has all the top growth), so that it forms one new plant.

A rootstock is generally made from a one or two year old seedling and needs to be healthy, vigorous and true to type. The top of the plant being used for rootstock is cut during or after the process of grafting (depending on the type of graft used). Where the rootstock plant grows well from hardwood cuttings, a cutting rather than a rooted plant can be used as the rootstock.

Rootstocks, particularly for trees, can be purchased from specialist nurseries (ensure you always purchase certified virus free stock) or you can grow your own. Whichever you do, the rootstock needs to be appropriate for the size and type of plant you want and compatible with the scion. If you’re growing your own rootstock then you can do so from seed, stooling or trench layering. You should aim for rootstock that is well rooted, straight, of medium thickness for the plant in question and about 45cm tall (or taller if required, eg for top working a standard).