Both Lucifer and the Shasta daisy tend to get a bit out of bounds as they mature. I experimented this year giving the Shasta a 'Chelsea chop' in mid-June which worked well to keep it from getting too tall. Lucifer I try to stay on top of by cutting back the seed-heads when they start leaning out into the lawn. I relocated the gaillardia this year (too much yellow) and plan to replace with perhaps a later blooming purple aster or a salvia.