I'm not sure it would be divisible, that type of Rudbeckia is short-lived and doesn't necessarily overwinter, where I am anyway. It's not like 'Goldsturm' which is reliably perennial, it looks more like an 'Indian Summer' type.. I keep the latter going from self sown seedlings. I think you'd have to save seeds, at least as back-up, and keep crossing the seedlings most like it until you get a true breeding line. Or try and sell it to a company that breeds and markets annuals. That's just my thought based on the type it appears to be in the pic.
