By Gardenstan
I have "Sugar Maple tree" about five years old.
All the leaves are covered with small blister type growths.
These are red and also green.
Could you tell me what is causing this ?
Thank you
Stan Hirst
17 May, 2011
They're probably galls caused by acer gall mites.
http://www.donsgarden.co.uk/pests/336
They're not seriously detrimental to the tree although they are a bit unsightly. I don't think there's anything you can do about it.
18 May, 2011