I did it once and LOVED the result! I sent in my $10 donation and they sent me 2 bradford pears, 2 washington hawthorns, 2 dogwoods, 2 redbuds, and 2 flowering crabapples. They come as "bare root"
trees.
What I did was soaked the roots over night and then planted them in pots. After they went through 2
growing seasons in the pots, I placed them out in the yard. The Redbuds did the quickest
growing and were blooming the following year. The best thing about them was that my husband accidently cut one down (before I put cages around them) with the riding mower, but it came right back more vigorous than ever!
I guess to answer your question, you just have to decide how much you want to "baby" them at the begining! Good Luck!
Annette