I have roughly 1/3 acre that has one hive but hopefully will move up to 4 this spring. I'm planning on planting bee friendly flowers in this area. I found a company called Applewood Seed Co, that seems to have an impressive mixture of wildflowers specifically for bees. Thought I'd toss it out for others if they are interested. I have never ordered from them as of yet, so can't provide an opinion negative or positive.
http://www.applewoodseed.com/pollinator/#HoneyBees
Chris
http://www.applewoodseed.com/pollinator/#HoneyBees
Chris