Photinia marble pink - dying?

Hello,

I am very new to gardening and hoping for some more experienced help!  

We bought two marble photinia trees four months ago.  Both are at the front of our house in pots and get about the same amount of sun and shade each day.  The one on the left has not thrived and despite resolving an issue with a waterlogged pot, feeding and watering regularly, it still looks very sad and we don't know what else to do.  The other one is thriving so they look very imbalanced now.

dying?

thriving!

Thanks in advance for any tips.