How far apart do I plant these knockout roses?

I bought 6 of these type of roses.

http://www.parkseed.com/webapp/wcs/store...



I am planting these in a line as a hedgerow. The information on the plants say they grow 2-3 feet wide. Since I want them to be basically like a fence (I don't want gaps between the plants), I'm unsure how far apart to plant them. Is it better to plan for 2 feet or 3 feet?

How far apart do I plant these knockout roses?
Two feet for the hedge is best. Spacing roses from 20 inches to 30 inches apart produces the best results. Wider spacing than 30 inches make the plants stand out as individuals and you lose the mass effect a rose hedge should present. Closer spacing than 20 inches will crowd the plants and restrict their growth.