Chapter 1

Grafting and budding

Grafting is a horticultural technique to produce a new plant by combining others, usually involving two plants but can involve more as in a ‘family tree’ made up of several cultivars. Most commonly one plant provides the rootstock and the other provides the scion (the top – stems and leaves). These are joined in such a way as to create a permanent union. For this to happen the plants involved must be compatible (typically closely related) and the join is made by bringing together cambium tissue in both plants. A graft can form naturally e.g. branches of a tree rubbing together until the cambiums are exposed on both branches and press together as they grow until a union is formed. Commercially it is undertaken by skilled horticulturists. Budding/bud grafting is when a bud is added to the rootstock rather than a shoot; this is often preferred as it makes better use of scion material.

It is a labour intensive activity so it tends to be used when other methods of multiplying plants are not available. It is also an important means of producing plants by combining advantages in order to provide plants with enhanced characteristics mainly by joining a desirable scion to a more suitable rootstock:

• resistance to a soil borne pest (e.g. grapevines and Phylloxera) or disease
• vigour reduced in scion by using ‘dwarfing or semi-dwarfing rootstock’ (e.g. most apple trees; cordons, stepovers, bushes)
• vigour increased in scion
• sturdy stems (e.g. standard roses)
• cold tolerance
• speeding up the time to flowering and/or fruiting (by-passing juvenility)
• creating ‘family trees’ either for novelty (several cultivars on one tree for a small garden) or to provide extra pollinating material in an orchard.

It is also used to change a tree cultivar by replacing it with an improved one, ‘topworking’, without having to establish a new tree. Commercially it also can help spread the workload over the year as much of it can be done in what can be a quiet time of the year in many nurseries (February to March).

Grafting outdoors/open ground is usually referred to as ‘field grafting’ and that undertaken under glass as ‘bench grafting’.

Methods

Bench grafting includes

• side veneer and lip
• spliced side veneer
• veneer graft
• saddle graft.

Field grafting includes

• whip and tongue.

Common budding includes

• chip budding
• T-budding.