Mums all over again

It's that time of year again, and the volunteer mums are blooming all over the place. I moved these self-sown seedlings from the front flower bed, and tried to get rid of the less attractive ones in the process. It's really hard to throw them out when most of them are so vigorous and enthusiastic. I need to get myself psyched and be more ruthless, because I'm sure they'll reseed more afterwards anyway. The two reds on either side in the first picture were the most vigorous of that color, but they still aren't quite up to the standards of, for example, the light yellow in the second picture. It's more yellow than the picture shows it, and is a HUGE, sturdy, mounding plant. I'm pretty sure most of these are derived from the unidentified pinkish Korean mum I bought many years ago. It was in a little 4 inch pot nearly dead and on clearance for a quarter at a local home improvement store. I grew it for a number of years and never saw any seedlings, but when I moved it to our new home and a house-warming gift mum cozied up nearby, seedlings started showing up everywhere the soil was bare. Now some more recent gift mums have joined the fun and contributed their genes to the expanding seedling population.