Are there side branches or tips that you can let grow to 3 leaf nodes? If so, take a tip cutting just like you would do in spring, pot it up, winter it over as an indoor plant, plant it out in the spring & hope the sport stayed true. Seeds won't be true but if you collect some & plant them in the spring you might come up with some interesting other blooms.

Thanks, Plantlady. I'm assuming the side branches would have to come off the same branch the yellow bloom is on, right?
I'll check this aft when I go water, if I water. So far no new blooms on that plant to check but I'm watching like a cat with a cornered mouse...LOL.

Speaking of, thanks to your earlier advice ole Poochella has three cuttings that have bloomed to date and more on the way. I had a great number that rooted, took them upstairs for more heat only to have them mowed down like a salad bar by the cats! Think I should adopt dahlias instead of animals....

So thank you on two counts! I'll post if anything happens with the sport.

WOW! I love the yellow sport of Riverdance!

My Ducks decided they loved dahlias and ate all the red ones I planted into my red garden! I have Fire and Ice coming back ,now that the ducks have been in a different garden for 2 weeks and I hope the one behind it is Riverdance.

Yes, you have to take the cutting from the sported branch.