Hi John,
Amazing stuff !! I am always saying that zinnias are full of surprises, and your color-changing zinnia is one of those surprises. There may be some funny genetics going on in that zinnia.
And another thing, not the same as what your zinnia just did, I have seen surprising differences between one zinnia branch and another. It's almost as if "bud sports" were a common thing with zinnias.
These are are a couple of my current zinnia blooms that I like.
That last one reminds me of a carnation. Its petal ends are extremely "toothy".
ZM
