Ficus (banyan) roots
I live in lower Manoa and have a VERY large ficus tree in my yard, planted by the previous owners. It is probably about 30' tall. There is another smaller (20'?) ficus growing about five feet away from it. The larger ficus' shoots are growing on and over the lava rock wall that forms my backyard boundary. We are interested in putting a small wood fence on top of the lava rock wall for additional privacy but wonder if it is possible to cut away some of the shoots that are growing over the wall or if that will compromise the stability of tree or cause parts of it to die off. Honestly, I wouldn't mind if the tree were gone (the roots are a pain--all over the backyard) but I don't want large branches to die and fall from overhead and hurt someone.
Also, what type of grass will grown in a backyard that is partially shaded by this large ficus? I've read that St. Augustine grass is shade tolerant and hardy.