I have to admit you are sort of doing what I did with my mums. I started with 5 identical purple mums at my side foundation. After that I took out some overgrown foundation bushes, and delayed on deciding what would be more appropriate in their place. Meawhile the mums were seeding, and this went on year after year as various recessive genes emerged. There are now a multitude of colors. All ranges of pinks, bugundy, scarlet yellow, white salmon, orange. And all forms including some large, some with spoons, some as small as chamomile. And the hover flies love the small white ones, and they gobble down aphids like crazy.
The mums worked their way around the corner of the house and populated the front foundation area where the bushes had been. And of course all that survived had superior winter hardiness. I helped out ones that I especially liked by dividing them. In back of them I planted Moonshine yarrow for earlier color. And back of that I planted russian sage whose lavender spires sometimes reach as tall as the front windows. In early spring I cut everything back practically to the ground and use the same hedge shears to "disbud" at least twice before July 25. Last year I missed a disbudding and they overgrew a bit. But no biggie.
Now I've had neighbors I don't know walk clear down our street to gawk at my mums when they bloom.
This is what they looked like last fall.
