Cleft grafting is a horticultural technique used to join two plant parts together, typically a rootstock and a scion. This method is often employed to propagate fruit trees, such as apple or pear, by attaching a desired variety (the scion) to a sturdy root system (the rootstock). The process involves making a vertical cut in the rootstock and inserting the scion, which has a wedge shape, into the cut. This technique is particularly useful when the scion is smaller in diameter than the rootstock. Cleft grafting allows for better compatibility and growth, as the cambium layers of both parts must align for successful healing. When done correctly, this method can lead to a healthy, productive plant.