Grafting grows several varieties on one tree. The Amish graft apples, pears, cherries.
Why
Cross-pollination (need 2+ varieties). Saves space. Fast harvest (grafted scion fruits in 2-3 years, seedling in 7-10). Variety preservation (seeds don't reproduce true).
When
Early spring, before bud swell. Sap starts flowing, tissues actively growing — maximum success.
Technique (Cleft Graft)
Cut rootstock horizontally. Split 5 cm deep. Sharpen scion to a wedge. Insert so cambium (green layer under bark) aligns. Wrap with tape. Seal with grafting wax.
Success
Cambium alignment is key. If scion and rootstock cambium don't touch — it won't take. Success rate for experienced: 80-90%.