Q.Can I Mix Species In A Hedge And Still Have A Cohesive Look? And, Can I Divide Boxwoods To Fill In Gaps In A Hedge?
I planted a square of boxwoods, spacing them 3 feet apart. I would now like to fill in some of the spaces to hurry the process along a bit. (1) Can I mix species – Winter Gem, Franklins Gem, etc.? and (2) Can I divide them in halves or thirds to get more “fill in” plants?

Certified GKH Gardening Expert
You can mix species, but I would stick to the ones that have similar coloring. For example, Franklin's Gem foliage turns olive green, which might not be the same color green as your other boxes.
When you buy more boxwoods, examine the stems if you are going to try to divide them. Use a spade to separate the rootball in two pieces. You may like to try propagating the ones you have from cuttings. Here is more:
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/common-boxwood-varieties.htm
https://www.gardeningknowhow.com/ornamental/shrubs/boxwood/rooting-boxwood-bushes.htm