Grafting — Joining a Scion onto a Rootstock

A graft joins the TOP of one plant to the ROOTS of another. The scion — a shoot of the variety you want — becomes the branches and fruit; the rootstock becomes the roots. They knit together at the join and grow on as one tree. It is how almost every apple, pear, cherry and citrus tree is made.

Take a dormant, pencil-thick length of last year's wood with a few buds as the SCION (the variety you want to copy), and a compatible rootstock of similar thickness — apple onto apple, pear onto pear or quince. This is essential because fruit trees do NOT come true from seed, and the rootstock also sets the tree's final size and toughness.

For a whip-and-tongue graft, cut a long matching slant on the end of both scion and rootstock, then cut a small interlocking 'tongue' into each so they hook together. Use a razor-sharp grafting knife for clean, flat faces — ragged cuts won't knit.

Slot the two together so their CAMBIUM lines up — the thin green living layer just under the bark. This is the make-or-break of grafting: only where the two cambiums touch can they grow together. If scion and stock differ in size, push them to one side so at least ONE edge of cambium matches perfectly.

Bind the join firmly with grafting tape or twine so the two can't shift, then seal every cut surface with grafting wax (beeswax-based) to lock in moisture. A graft that dries out before it knits will die, so seal it airtight.

Keep the graft union above soil level and protected. As it grows, rub off any shoots (suckers) that sprout from the rootstock BELOW the join — those are the rootstock's own variety, not your scion, and will steal its strength. Label the variety and date.

Over the coming weeks the two form a bridge of callus and then shared plumbing. When the scion's buds swell and push out into leaf and shoot, the graft has taken — the water and food are now flowing across the union. Loosen the binding before it bites into the swelling stem.

Grafting turns on one tissue: the CAMBIUM, a whisker-thin sleeve of living, dividing cells sandwiched between the bark and the wood, which is the only part of a stem that can grow new tissue outward. When two freshly-cut cambiums are pressed tightly together, each throws out a mass of undifferentiated CALLUS cells; the two masses meet, fuse, and then organise themselves into continuous new plumbing — xylem to carry water up, phloem to carry food down — so the two separate plants become one connected vascular system. That is why lining up the cambium is everything, and why the join must be bound tight (no movement) and sealed (no drying) while it happens. Like a cutting, a graft is VEGETATIVE propagation — the scion growing above is a genetic CLONE of the tree it came from, so the fruit is exactly the parent variety — but grafting adds a second plant underneath, making the tree a deliberate two-part chimera: a chosen top on chosen roots. Why bother instead of a cutting? Because the rootstock is a tool. A dwarfing rootstock keeps an apple tree small and quick to fruit; another gives disease resistance, cold-hardiness or tolerance of heavy soil; and many prized trees (and most fruit) simply won't root from cuttings at all, yet graft readily. You can even graft several varieties onto one 'family tree'. The one rule is COMPATIBILITY — only closely related plants will knit (apple takes apple, not oak). Beyond whip-and-tongue there is the CLEFT graft (wedged scions into a split stump, for topworking a big tree) and BUDDING (slipping a single bud under the bark in summer, the nurseryman's fast method). Practised in China and the Roman world over two thousand years ago, grafting is the ancient key that lets a single perfect fruit tree be copied, sized and toughened at will — the backbone of every orchard.