Question
I have noticed a green collered growth on a tree in my yard. It looks like little shamrocks and seems to be spreading to other palnt life nearby. What is ut and what can I do?

Answer
It sounds to me like you are describing lichens.  These organisms are a symbiotic relationship between and algae and a fungus.  They are not harmful to plants and can be found on just about anything.  They vary in size, shape and amount ocurring on plants.  There is no need to attemp to remove them.  Make sure that plants with lichens are not stressed by drought or lack of fertilizer as occurrence of lichens is usually a sign that a plant is stressed by drough or old age.  Some are light green to gray in color and can look like little flowers or other forms on the trunk of trees. Do a google search for lichens and view some pictures to see if this is what you are describing.  If this is not the case, please respond back and we will go in another direction.  Thanks.