Grafting

What is grafting?

Grafting is a method of vegetative propagation in which living parts of two plants are joined so that they grow together as one plant. The upper part, called the scion, provides the desired shoots, leaves, flowers and fruit, while the lower part, called the rootstock, provides the root system and usually the lower stem.

When is it useful?

Grafting is especially useful when the characteristics of a selected plant should be preserved but propagation from seed would produce variable offspring. It can also combine desirable characteristics of a scion with useful characteristics of a rootstock, such as adaptation to particular soil conditions, disease resistance or influence on plant vigour.

Basic procedure

1. Select healthy and compatible scion and rootstock material.
2. Use a clean, very sharp tool to make suitable matching cuts.
3. Join the scion and rootstock so that their living cambial tissues make good contact.
4. Secure the graft firmly with appropriate grafting tape, wrapping or another suitable material so that the parts cannot move apart.
5. Protect the graft from excessive drying, contamination and physical damage while the tissues unite.
6. Monitor the graft and remove unwanted shoots arising from the rootstock when appropriate.
7. After a strong union has formed and the scion is growing successfully, remove or loosen binding material when necessary to prevent constriction.

Scion and rootstock

The scion is selected for the characteristics desired in the above-ground part of the new plant. The rootstock is selected for its root system and may contribute characteristics such as vigour, size control, tolerance of particular soil conditions or resistance to certain pests and diseases. The actual effects depend on the species and rootstock-scion combination.

Compatibility

Successful grafting requires biological compatibility between scion and rootstock. Plants of the same species are often compatible, and some closely related species or cultivars can also be grafted successfully, but compatibility must not be assumed. Even apparently successful grafts may fail later if the combination is incompatible.

Cambium contact

A successful graft depends on close contact between the living cambial regions of scion and rootstock. The pieces do not necessarily need to be the same diameter, but their cambial tissues must be aligned sufficiently for new connecting tissue to form across the graft union.

Different grafting techniques

There are many grafting techniques, including cleft, whip, splice, side and veneer grafting. The appropriate technique depends on the species, the size and condition of the plant material and the purpose of the graft.

Grafting and budding

Budding is closely related to grafting but is recorded separately at Yuyo. In conventional grafting, the scion usually consists of a section of shoot carrying one or more buds. In budding, a single bud with a small amount of surrounding tissue is inserted or attached to the rootstock.

Important

Compatibility, grafting technique, scion maturity, rootstock condition, season and aftercare vary considerably between species. Always check the species-specific propagation information before attempting a graft.