What is Killing my Gardenia Hedge?

Please help! We don't know what is happening to our once beautiful gardenia hedge. See pictures below.

The hedge sits along the length of our driveway. It is well established as you can see. This is a photo of it in its entirety. The destruction started closest to the house (right side of photo) and has slowly started creeping along the length of the hedge. It began with browning of the leaves halfway up the plant and has spread from there.


Extreme close-up of the plant. All branches are still green when scraped and there appears to be some new growth coming out in places.

Angled photo down the line of the hedge facing away from the house.
A closer shot of the worst hit plants.

This photo was taken 5 days after the others posted above. I am not sure if it is better or worse. It definitely seems more bare but it could be a result of the recent heavy rain we have had that may have cleaned off the dead leaves.