In this week's edition of "doing it wrong", My wife and I have started what shall eventually be a hedge around the garden. From seed. because it was easier.
Fortunately, a garden does not typically require a barrier, so the fact that this will take a few years is not a show stopper.
Around the perimeter of tilled soil I planted about 70+ maple seedlings in 18 inch increments. If any don't make it through the year, I'll be able to find plenty of replacements. I also figure that after one year, they'll be tall enough to easily distinguish from the grass and whatnot. after two years, I should be able to start tying them together with grafting tape into an actual hedge. After five years, I'll actually be able to call it a hedge.
Another thing I acknowledge doing wrong is the lack of anti-weed netting. It's going to be a bit of a problem when the grass starts growing up and trying to infringe on the future hedge. I think that bit of laziness is going to cost me a couple of days this summer/fall and maybe next spring going about with a set of hand clippers trying to cut down the grass without damaging the young trees. After that though, they should be tall enough that I can safely spray the ground around them.