Need privacy under high-skirted cedars
We have a dozen huge (30-50 ft tall) cedars along the south border of our back yard. The branches were growing way out into the yard making it look dark and claustrophobic, so I high-skirted the trees to about 10 feet. It looks much neater, but now we have lost some privacy. We can see right between the trunks (which range from 5-10 feet apart) into the neighbor's yard. What can I plant between the cedars to fill in the gaps that won't grow way out into our yard?