Ideas for bed infront of white picket fence?

The area in my front yard, in front of my picket fence, is my current problem area - and I can't figure out what to do with it.

The area is about 3 feet by 170 (spanning our entire front yard). The first year we grass infront of the fence, and this turned out to be an awful chore to maintain - especially with the need to weedwack along the fence on both sides. We almost pulled the fence out - but I really like the fence. The second year we tilled the entire bed and planted a wild flower mix - both annual and perennial. Bed looked great the second year - great source of cut flowers, lots of color. No need to weed wack either side of the fence because the wild flowers were wild enough that they poked through the other side and looked great - hid the tall grass/weeds. This year, the third year, wild flowers that returned were few and far between, and the bed looks absolutely ragged and wild with no flowers or colors. I hesitate to mow it down without a plan. I don't want to have to till and reseed the wild flowers every year - so I think I need to move away from the wild flower. Other thoughts that I have: thick planting of daisies; or mixed day lillies; or medium height groundcover that is green from Spring through fall; ????

I don't mind putting the work in upfront, but would rather the work reduce in maintenance each year.

Any suggestions? Thanks!