Q: We planted twenty hemlock trees six years ago. We have lost a few but for the most part they have done well. It seems this summer that they are not as green and are not growing like they have in the past.
A: Hemlocks require three things in order to prosper: drainage, drainage, and drainage. Although I see towering examples of healthy hemlocks in Atlanta, I see many more that live for a few years and then decline.
Hemlock roots need conditions similar to the mountains where they are native: rocky soil that does not allow water to stand around the roots for any period of time, yet regular rainfall so the soil doesn’t dry out. This summer has been the bane of trees that hate wet feet. I’ve heard loud wails from flowering cherry owners regarding their own tree tribulations.
Look at it this way: your hemlocks that survive this summer are pretty well guaranteed to have a long life afterwards.