Question
Hi there how are you doing? We have a Avo tree in the back yard bout 30ft high already. And it is growing bigger every hear and it is sort of forming a bush as well. Now I have 2 questions what can I do to sort of thin the tree out and make it grow more in a upwords position rather then bushy and then the graas under the tree, well there is no grass under the tree. What grass type can I use that will grow or what do you suggest.
I am not online all the time so E-mail respond will be great thanx.
Have a good day
Regards Heine

Answer
Do you know if that avocado was grafted? If yes, then 'suckers' will grow from the trunk below the graft. All such suckers should be cut away. If left in place, they will rob the tree of nourishment and will not produce any good fruit. I am not sure if the avocado sends up root shoots. These are shoots that arise from the roots of the mother plant and are similar to suckers. These also should be removed. You will then have a clear area around the tree. It is not a good idea to plant grass under the canopy of the tree because the roots of the tree will make mowing very difficult. Additionally, when you treat the grass with fertilizer and weed killers, the tree might not like it. Outside of the tree canopy, or drip circle, you ought to grow grass well. Just be careful with the weed killers because the feeding roots of the tree are concentrated in this band and will pick up any chemical in this area.  
I am sorry that I do not know enough about your location to make a recommendation about grass type.