Patrick,
You can plant somewhat close in that 9' bed., 15 to 18" between clumps left to right. Try staggering the clumps of each variety in a zigzag fashion with 6 clumps in the rear row and 5 in the front, but make the front ones offset from the rear with clumps centered on the spaces in the rear row giving a 15-18" diagonal spacing. This will allow a few more clumps to fit in the "small" area.
dave
