In late March I planted 12 crepe myrtles down my driveway. Eight have leafed out, four have not. I've done the scratch test on the bark and they show green. My question is: I've been told by other gardeners that some could take up to a year to leaf. Is this correct? They are 10 feet tall and were not in pots.
Certified GKH Gardening Expert
This can be true, but I would try to get them to leaf out if possible. Trees need the energy stored from their leaves in spring and summer to help them survive the dormancy and rigors of winter. If they don't leaf out, it does mean they will not survive winter, but it does mean they will have a higher chance of dying over winter.
For now, I would treat them as though they are in transplant shock. This article will help with that: