Blueberries are a fairly common nursery plant if you have a good look and are looking for blueberries specifically. Go ahead and get one in a nursery pot right away and get started with that--make your mistakes on that one. Then you'll have that much more experience under your belt before you go collecting one. If you don't have much experience collecting from the wild, your chances will be much improved because you've gained some confidence on your nursery tree beforehand. Getting a nursery-grown tree into a bonsai pot is a little like collecting in the root work that you have to do to get the tree into the pot. Practice on that too
