Shadegardener... The picture I posted is a little deceiving. The grass actually stops about a foot from the base of each tree. There are a couple grass clippings near the base, just due from a recent yard mowing. Between the grass clippings and the quality of the picture, that is probably why it looks like the grass goes up to each tree.
I can definitely do a yard waste compost! Do I literally just gather up the grass clippings and spread them around the bottom as is? Or is there a process? LOL So sorry for my ignorance on all this!
And yes, we use a weed killer on our grass. We also planted arborvitae about 10 years ago a little further down our yard. (These were planted by a different guy.) I will attach a picture so you can see the difference in these trees. Clearly, about 7 years separates them in age, but the large trees are just so healthy. I figured I should provide a picture.