Good dwarf bowood for mid-atlantic
I'm designing an herb/potager garden area for my house in which I would like to use boxwood as an edging plant. I love the color and traditional smell of buxus sempervirens, but that gets to be 6x6' tall eventually and this is a small space where I want the edging plant hedge to be no more than 18"-24" in height and width.
What is a good dwarf variety that can easily be maintained at this height and not too subject to browning out?
What is a good spacing distance to plant them? Is 18" apart too wide?