Transplanting Tree Sprouts

Q. I'm delighted to have found your blog! I just found out the Kwanzan
Cherry tree we loved so much but had to cut down (carpenter ants
destroyed the trunk) left us some sprouts. I'm not sure how many are
there yet - they are under a ratty looking pine tree so I have to crawl
under and see. I want to transplant at least one of the sprouts.
What's the best approach?

A. What a happy discovery! How long has your Cherry been "gone"?
I have a few questions for you since your "sprouts" seem to come from the trunk of your tree. Have you checked to see if the sprouts are "free standing"? Or are they sprouting from the stump of the tree? If they are growing OUT of the STUMP and are actually PART of that remnant stump, I'm afraid you'll have to leave it there. Pick the biggest and healthiest looking sprout to be your new tree. Cut out all the rest of the sprouts and say hello to your new tree! Once you've picked the final sprout to favor, cut out any others that grow up to compete with it.
IF it's a sprout that should be cut away, I'd do the cutting now, leaving the tree IN the ground where it stands until it's ready to transplant. Kind of like operating on a Siamese twin, but leaving it IN PLACE. That way, the shock of moving it will be less traumatic. Your best bet would be to wait until early fall to do the actual transplanting so it doesn't have to struggle through a hot summer.
While it sits there, separated, but in place, begin to prepare it's new home. I assume by now you've decided where it wants to be? Remember it will be in the same place for the rest of it's life, so make it GOOD!
Be sure this site has the proper amount of light and shelter. If there's a hill, place it half way down, rather than at the top or bottom as it will be better protected from frosts and winds. Avoid placing it too close to a building, under wires, or over pipes and cables where it may need to be trimmed back. Choose a well drained site. No tree likes to sit it water.
While you wait, get a soil sample from this new location and send it to the State University Extension Service with a note telling them that it is where you want to plant a Kwanzan Cherry Tree. They will test the soil for you and tell you exactly what you need to add to the soil, if anything. That is the BEST gift you can give your tree.
When you begin to dig, work some compost into the hole along with whatever amendments the soil test has suggested. Usually the hole is dug 2-4 times the width of the roots, so they can be spread out. If there are any damaged roots, be sure to trim them off. Gently set the roots in the ground and begin to backfill the hole. Stamp the soil in well to avoid any air spaces and water it thoroughly. You might prepare a bit of a "dish" around it so the rain will stay there rather than run away. For the first few years, be sure your new tree does NOT dry out. It may need a little winter protection and perhaps a trunk wrapper wouldn't hurt for the first, few winters. Mulching around it will help keep the weeds down and the moisture in. So consider doing that as well.
Good luck, and Happy Gardening!