Chris, your Limelight is beautiful. Mine has been doing well this year with more protection from summer sun. The small patch in the semp beds struggled, so I place a pot in partial shade with some cutting in it. It took off like it was on steroids. I now know for my area some shade is best for them. They have not required much water at all, seem to be very drought tolerant, if given a little shade. More water is needed in in full sun here, even then they don't do as well here.
Marilyn, it does look like you make have been over watering them. Also, bunnies will eat them, but you would see signs of them being eaten.
It all comes down to finding what they want in your growing conditions.