Gardening Techniques: Grafting And Budding – A graft is a union between two plants, the roots and lower stem (the stock or rootstock) of one plant uniting with the shoot of another plant (the scion), so that they grow together as one. The main role of grafting in horticulture is the propagation of trees and shrubs where one or more of the following difficulties prevent easier means of producing planting material:
– Varieties which root slowly or not at all from cuttings or by layering.
– Varieties which do not set seed.
– Varieties which do not breed true from seed.
– Varieties which are unsatisfactory when grown on their own roots.
A mystique has grown up about grafting, but the principle is very simple. The stock and the scion must be related — as a general rule the chance of a successful union increases in direct proportion to the closeness of the relationship. Next, there must be physical close contact — it is the thin living layer below the bark which has to knit together.
Timing is important — the plants should be just starting to grow after their winter rest, and the union must be protected. This calls for binding with raffia, plastic tape or an elastic tie and then covering the whole area with grafting wax. This will prevent both drying out and infection from air-borne spores.
Although the principle is simple, a large number of systems have evolved over the centuries — saddle grafting, rind grafting, approach grafting, splice grafting and so on. The most popular method is whip and tongue grafting. The stock and scion should be approximately the same thickness — remove the binding material once the graft has taken and new growth has appeared.
Cacti are the easiest group of plants to graft. All you have to do is to cut the base of the scion in the form of a V. Cut a corresponding V at the top of the stock and push the two grafts together. Push a few pins or thorns through the union and leave the rest to nature.
Commercial roses are generally propagated by budding — a form of grafting which is carried out in midsummer rather than early spring. A bud or ‘eye’ of the selected variety is inserted into a T-shaped cut made in the stem of the rootstock — close to the ground for a bush or some distance up the stem for a standard.