Grafting is an advanced technique that botanists, farmers, gardeners, and hobbyists use to add living tissue from one plant to another. Plant tissues have the ability to grow new vascular tissue, and the process of grafting takes advantage of this ability. The vascular tissue of the main plant joins with the vascular tissue of the added plant, keeping the new tissue alive and growing. This is a way for plants to reproduce asexually. You can think of grafting as being similar to organ donation - when someone needs a new kidney or liver, they can get one donated.
Their body will grow new blood vessels, and the new organ will grow and work in its new body. The same thing happens with plants, except it's much less expensive!
One of the best example of grafting is 'Tree of 40'.
A Tree of 40 Fruit is one of a series of fruit trees created by the New York-based artist Sam Van Aken using the technique of grafting. Each tree produces forty types of stone fruit, of the genus Prunus, ripening sequentially from July to October in the United States.