I have 2 acers, one green and one dark red (don't know the names as they were from bargain bench in local garden centre 2 years ago and had no labels!) They are both in big pots in ericaceous compost. They are in shade most of the day apart from a few hours in the morning, and right beside the house so fairly sheltered. About a month ago the green one's leaves started going brown and shrivelling up, and all the branch tips are dying back. Now its happening to the red one too I have no idea what might be wrong or what to do, any ideas please? Thanks.