I have a magnolia on which the new leaves turn brown and die. The whole plant appears to be going the same way. In the same bed, a camellia which was fantastic last year, produced few buds which turned brown and never opened, also, all the leaves are turning yellow. I am feeding them with ericaceous food but things seem to be getting worse. I have heathers, fuchsias and a conifer, plus aquilegias which all seem fine. What am I doing wrong.Any ideas gratefully received.