By Jand
Northamptonshire,
United Kingdom 
Growing in the ground for the last 10 years + will try the horticultural soap thanks
3 Apr, 2011
By Jand
Northamptonshire,
United Kingdom
Growing in the ground for the last 10 years + will try the horticultural soap thanks
3 Apr, 2011
this must be the Magnolia lichen problem - Jand, hope it helps, but its easier if you add your thanks or acknowledgement under the original question, then we know what you're talking about, lol!
8 Apr, 2011