You can bud or scion graft onto compatible young trees. Can you identify the trees you have growing? Al

I will have to ask our Son. They are the kind of young trees, which grow free. I was thinking of using them to transform some roses scion into rose trees and also some hydrangeas.
Sometimes I get those kind of ideas, mostly when I go thru catalogs and see the prices!
Right now I am thinking of a squirrel stew, after I realize how many of my reblooming lilies have disappeared!

It is very unlikely you will be able to use your native trees as rootstock for anything in your garden. Check with your library for books on propagation that would help you with your project. If you know what rootstock you need you can grow your own either from seed or cuttings. When you buy a tree from the nursery they have been growing it for a year or two and have considerable labor expense, or they have purchased it from another nursery and need to make a profit to stay in business. Al