This year the All-America Selections trial has some sunflower entries, and we decided to direct seed those plots. Planting the seeds right into the flower bed is the common way most home gardeners grow sunflowers. Since a pre-emergent herbicide would have inhibited the growth of the sunflower seeds, we could not treat those plots as we usually do. It resulted in some great pictures comparing the use of a pre-emergent herbicide to the "two finger pluck" method of weed control! (The pictures were taken right after a rainstorm. The wet weather has kept us from hand weeding the sunflowers... Resulting in even more weeds!)
Farmers have a saying about how large a garden to plant: "Never plant a garden larger than your spouse will weed!" Most spouses don't weed gardens. Weeding is considered to be the least favorite among all gardening tasks. Pre-emergent herbicides can help.