Beautiful hedge is turning brown and dying in one area - What can the trouble be?

I'm watering it in that area more than the rest of it. It's a big, beautiful hedge, seemingly healthy everywhere but that one area. Since we are in drought, I didn't water it as much as I usually do. Now I'm watering the daylights out of that area, but it's not helping, Water and snail bate is all I know how to do for it. Any thoughts?