I'm no expert but spraying had nothing to do with the mutation. Double-decker purple coneflowers are now all over the place, so it sounds like your plant in white wants to do the same thing. I looked up the variety and it doesn't seem to be a hybrid. So, you can save the seeds and watch for the mutation in future years. I think you'd have to grow a lot of them, though, because the mutation may not be a part of all the seeds. You could try something I read about for tomatoes: plant about 50 seeds in a bucket as early in the season as you dare - you want them to try to flower in the first year of growth. Yank out all but 10 - choose the most vigorous. Let them grow that way for the season, but keep removing lower leaves if they overshade each other. Let the plants flower (but of course they'll be small in those crowded conditions). If you see the mutation in any of the flowers, save those seeds. The next year do it again. That way, in a very small space, you're selecting for the qualities you're looking for.

The other, much easier option, is just letting your mutating plant grow and dividing it each year. Maureen

Hi Maureen thanks so much for the info.