Question about trimming Gaillardia
Last spring I started several 'Arizona Sun' blanket flowers from seed. They grew slowly at first, but took off by midsummer, blooming prolifically until late December. Not expecting them to get so big (3'hx4'w!), I hadn't staked them, but they appeared quite content to simply flop over drape themselves beautifully down a small bank. Despite constant deadheading, most of them began to look scraggly and began to yellow in late January so I decided to cut them back. Now they're just sitting there, rather poor looking, with flimsy yellow stems, almost no leaves, and not one sign of new growth. (Other blanket flowers that were planted at the same time are still green and blooming, while other that sprouted from dropped seed are growing vigorously.)
Does anyone have any idea what went wrong? Was cutting them back a mistake? Could the stress of laying over instead of being staked have stressed them too much?