I have no experience with Boxwoods.

However, you'll probably need to hard-prune to induce back-budding.

Jason, here, just picked up a few home center Boxwoods. Maybe he
has advice. You can always attempt to e-mail, too.

One post is better than two. Folks are less likely to respond if there
are multiple Threads by the same poster. You can include links at the
bottom of the reply box.

Josh

Here is a link that might be useful: {{gwi:16042}}