I had two camellias planted in November (spring) by my landscaper, from the same nursery. They've been fertilised the same at planting and watered the same, and are only 3 feet away.
One is losing its leaves, yet the other looks fine. Three other camellias also planted the same time are also good.
I assume it's a root issue, but could it just be a feeding issue somehow?
And the normal:
Update 20 Dec 2016
The landscaper replaced this tree a few months ago. He said the root ball just didn't grow. And then today he came to replace another one, as well as plant a new one next to another sick looking camellia. So, we're talking about 3/6 either died or looking sickly. Yet I have other camellias in the same area that are doing well, though they're a broad leaf variety.
We examined the roots of the one we removed today, and some of the larger roots were not very strong, snapping easily or just pulled away. But lots of fine roots were present. So, not much closer to an answer. He's going to take it back to the nursery to ask them.