Posted: 10/09/2012 at 00:07
I was at the Wisley flower show yesterday and spoke to a lovely lady who specialises in acers - precisely because mine (a purple, palmatum, about 2 ft high) is also going greener now, as well as having slightly dried out/crispy edges to some of its leaves.
She told me that loads of their plants have been suffering too- the change in colour, she thinks, is due to the weird weather, with a late start for the warm season, at a time when the acers would normally be starting to wind down for the year. Apparently this awful Spring we had, and a relatively late summer which is still very warm for the time of year, has tired out lots of acers, especially the purple kind, which are putting less energy into their leaves at the moment.
She told me the crispy edges are normally due to lack of water.
She said the best thing is to feed it with a seaweed fertiliser, fortnightly until the end of October, then again in the Spring.
Hope this helps!