Please help, I'm hoping for any advice you can offer.

Last week I trimmed my hibiscus in my yard. It's been in the ground for 5 years now and is like a tree. I cut it back from about 9 feet high to about 6 feet leaving lots of shoots to grow. It has several branches coming out of the base that are about the size of my forearm. The main problem is underneath this tree is a city easement. It's a beatiful plant/tree but I'm afraid that not only will it get too big for me to maintain but it could possibly harm the easment below. I'd hate to dig it up but if it's growth keeps going the way it has been I may have to.