Boxwood is pretty straight forward to start from tip cuttings. I usually use a cutting about 4 to 6 inches long with most of the leaves removed. I use tented containers on a 70 degree heat mat with a primarily perlite mix. I would allow about 2 months time for rooting enough to transplant. Al

My experience rooting boxwood was successful. After trimming 2 large globe BW topiaries, I decided to try propagating a few sprigs before composting them.
I had some left over landscape pots so I mixed 50/50 sand and potting soil and filled the pot 1/2 fill so to cover it if necessary. Which I never did.
I ended up doing 4 pots with 4"-7" sprigs just a few inches apart. I did use rooting hormone. I sat the pots behind some holly bushes, in the shade, and watered when it did not rain to keep them moist. I just left them thru our very bitter cold winter and then checked in March and was surprised they had rooted.
I potted each up in 1.5 liter water bottles that I saved, cutting off the tops and punching holes in the bottom, in potting soil. I now have 78 pretty little boxwoods sitting in my open cold frame. There were 11 that did not root. I'm imagining all kinds of things to do with them.