Leaves on Salix Nashiki Willow Turning Brown?

I purchased two salix nashiki standard plants. They both were very healthy. They are planted in pots with fertilizer and bonemeal + feed. They are not short of water, but not overly watered. The green leaves on 1 started going brown and crispy working down the 'branch'. A week later the other one started the same way they both look very sorry for themselves now. The white/tinged pink leaves have also stated to turn brown.

By Brenda