You can purchase Kristen sweet cherry trees from a mail order company by the name of Miller Nursery. I am growing a new cross between a sweet cherry and sour cherry that seems to be perfectly hardy in zone 4 called "Danube" or "Hungarian" Cherry. It has not born fruit yet but I'm excited to see what it ends up producing.

Thanks for the info, I actually found Miller Nursery a few weeks ago and placed a order with them, but I have not got the trees yet, hopefully they are a good company. I ordered a Kristen and a Black Gold. You will have to keep us posted on your new tree. Will the tree be a sour or sweet cherry?

It will be interesting to see how sweet the hybrid cherry will end up being, but it sounded like it would be a sweet cherry with some of the flavor of the sour-type cherries. I'm hoping next year it will bloom and produce fruit. The tree itself is quite vigourous and looks very healthy after -20 F. temperatures this winter.