The Green Mountain boxwood is a moderate grower to 5 feet tall, 3 feet wide. I'm not sure if I understand the total linear feet of hedgerow you are wanting but it seems to be about 7+12+7=26 linear feet (if you go around 3 sides). Those plants can be planted as far as about 3 feet apart although 2 1/2 would make a little faster hedgerow, and a more solid one. Your 8 plants at 3 feet apart would reach about 24 feet which is pretty close. I'd probably choose to start with 10 plants (10 X 2 1/2 ft. = 25 linear feet of hedge). Use my figures above to redo the math if I misunderstood the yard dimensions or feel free to submit another question to the Monrovia website and we'll be happy to help further.
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