A graft is a living joint that binds the root system of one plant to the shoot wood of another, so the pair grows on as a single tree.
Grafting is how a grower keeps a variety true to type. Wood cut from a proven tree carries the same fruit, the same habit and the same ripening window, while the roots underneath decide vigour, soil tolerance and how soon the tree begins to bear a crop. The join stays visible for life as a swelling above the soil.
Orchard work leans on two families of graft: bench grafts, cut indoors on dormant stock through late winter, and field grafts, worked on standing trees once the sap has started to rise. Bench work batches well and stays clean, so nurseries lean on it. Field work asks for a steadier hand, but it lets you turn a mature tree over one single limb at a time.
Rootstock selection
Rootstock sets the finished height of the tree far more than the variety on top does. For guidance on sizing classes, see vigour bands and the M-series reference chart.
Choose the stock before you choose the scion. Depending on the ground, the same variety can finish at two metres on a dwarfing root and eight on a seedling one, so the spacing plan has to be settled first.
Match the stock to the soil you actually have, not the soil you would like. Wet clay ground rules out several of the shallow-rooted dwarfs, whatever the catalogue claims.
Scion preparation
Cut scion wood while the tree is fully dormant — ideally in the first cold week of the year — and keep it wrapped and chilled until the stock is ready.
Take one-year wood of pencil thickness with three to four plump buds. Avoid the soft tips and the fat spur wood; neither one moves reliably once it is joined.
Label every stick as you cut it. Two varieties look identical in a bundle by February, and a mislabelled row will not show up for another three seasons.
Aftercare
A fresh union is a wound the tree is still closing, so the first eight weeks decide whether the graft takes. Keep the wrap tight, the cut sealed and the stock clear of competing growth.
Rub out every shoot the rootstock throws below the union. Left alone, they take the water and light the scion needs, and a strong stock can starve a good graft in a single season.
Release the tape once the union has swelled but before it bites into the bark. Late release girdles the stem, and the tree will snap at that point in the first real gale.