Question
Hello!
We purchased a beautiful lion's head maple tree last spring. Lately, it has developed a greenish coating on the trunk and branches.  Is this normal?  I hope it is not dying.
Thanks for your advice.
Christie

Answer
Sounds like a lichen. These are combination of algae and fungi and live on the bark of trees. They do little harm to a tree. As long as the foliage is green and healthy looking the tree is ok. I would water it during dry periods with 1 inch of water --place a pan under the tree and turn the sprinkler on and when the pan has 1 inch of water in it stop. Also if you have not done so i would mulch around the tree with not more than 3 inches deep of organic mulch not piled up on the trunk. This will help hold moisture.