The trees must be trained to grow as you see them in an orchard. Once a graft has been completed and the tree begins to grow, it will first appear as a single bud shooting up from the ground. One branch will grow off of this bud and produce many more buds. While the plant is in the nursery, workers must prune the tree and shape the branches into the normal tree shape. Sometimes the men and women who grow nursery trees want to find a new and different type of tree.
Sports are buds which have mutated into an entirely new type of tree.
For example, conifer sports have resulted in dwarf, twisted and weeping versions of the original plant. These sports can then be grown as nursery plants.