We live in middle Tennessee, and have a good-sized holly growing about
four feet from the house. It's roughly spherical, approx 8ft tall and
6ft across. I've just finished trimming it to keep its shape, but
every year it gets bigger and bigger.

To me, it looks like an asteroid that barely missed the house.

I don't think we need to take it out entirely, though that's a
possibility (we took another out about two years ago that was blocking
the front window. We're still dealing with the roots.). Instead, can I
prune it back dramatically to the trunk and a few major branches so
it'll be smaller and have a more natural shape? How long does it
usually take before leaves come in and it looks presentable?

Thanks!

--Nan