I have inherited a neglected box hedge. The foliage is on the outside of long woody stems and branches about 18 inches from the main stem. Can I cut it back hard to narrow the hedge and, if so, when? Also, when will the new foliage appear? Thanks.
You can attempt a rejuvenation prune, which can help open up the plants to allow sunlight and air flow. If no part of the interior is producing leaves, this may leave you with nothing.
Early Winter is the best time to do this type of prune.
Boxwood are slow growing.
Here are some links with more information.