Tie a scrap of fabric onto a stick and jam it in the flower box. Add the branches that you just snipped off the shrub that grows too fast. Realize you need more yellow, and cut from the flower you don't know the name of, and poke them in as well.
Voila. Perhaps no one will realize that you killed off all the color. Perhaps they will think you have gone a little crazy. Perhaps you have. Gone a little crazy.