Buy the 2015 Old Farmer's Almanac!
Sunflowers do well in prairieSunflowers do well in prairie fields in years that perennial weeds do not. In a sense, they are both competitors and also complement each other. Here is a good page on preparing a field for sunflowers: Keep in mind that pre-plant herbicides affect other prairie species.

2015 Garden Calendar2015 Weather Watcher's Calendar2015 Recipes Calendar2015 Engagement Calendar 2015 Everyday Calendar2015 Country CalendarNew Year Cross StitchLobster Rope Doormats