Experts and BHG readers answer.
damaged leaves of my Jack Frost/Brunnera
Thanks for writing. Without being able to see your hydrangea, I can't be sure of what's going on with it. Black leaves could signify rot, so letting it stay a little drier may help. Do you have mulch over the soil? A 2-inch-deep layer of mulch will help keep soil of the leaves. I wouldn't expect that to make them stop going black, but it should keep them cleaner and reduce the amount of weeding you have to do, too!
Also: How much sun does it get? Too much hot afternoon sun is bad for the plant. Do you fertilize? Brunneras are relatively sensitive to too much fertilizer or salt in the soil, as well.
---Justin, Senior Garden Editor, BHG.com