RoundUp is quite a bit more than just "grass killer".....otherwise it would have no effect on any non-grass plant, like your hydrangea :-)

But it takes a lot of the stuff to kill off a woody plant like a hydrangea shrub. It can certainly affect the foliage, causing it to dry, deform and drop off, but it is unlikely to have any permanent effect.

I'd just leave it alone for now and see how it responds in spring. It is very possible you will not notice any ill-effect but any deadwood can be pruned out then.

It won't hurt to flush the planting area well with plenty of water. That will dissipate any of the herbicide that might remain present in the soil.

Thanks. I’m not sure what he used, but it’s enough to keep vines under control. I assumed Roundup.

Thanks for the help!

Hello, mmp01. I was just wondering if this has happened before or if this is a new Limelight shrub. If your neighbor "controls the spaces in between the two fences in order to kill any vines", how come -on this particular time- his action affected your Limelight? I would have expected that the first time that he applied the grass killer/Round Up/etc, that this would have also affected the Limelight too?

This was a one time deal. The previous neighbor physically removed as much as he could a few years back. We usually manually keep it in check, this year we dropped the ball.

We don’t like to use chemicals, but the vines started growing through my side of the fence, Wrapping around boards, and into my LLS. I asked the neighbor if he had anything to blast it with, so he did me the favor.

Hopefully it grows back.