Brooding On

Loropetalum: What's Going on Here?

With the drought we had this summer, I'd expect to have plants dying.  But, this I just don't get.  See the very much alive and blooming plant on the left?  And the very much dead and dry plant on the right?
These plants, are Loropetalum, commonly known as Fringe Flower or Chinese Witchhazel.  They were planted at the same time (maybe 5 years ago?) and receive the same amount of water and sunlight.  They are (were) well-established plants that had previously lived up to their claim as low-maintenance plants. 

Beautiful blooming shrub

Dead-as-a-doorknob shrub

So, more experienced gardeners, what's going on here?  Obviously, the situation is beyond the point of asking for suggestions.  But, I'd at least like a little explanation so that I can avoid this problem in the future.

Hmmm.  That sure is a guilty look.  Is there any way Dexter could be culpable in this?