Greetings all. I'm putting together a school garden project for my son's preschool, and I'm looking for sources of heuchera seeds. The kids are going to 'winter sow' seeds in recyclable containers and then keep track of their growth in their science journals. I'm really hoping to find some seeds from the varieties that have either chartreuse/lime leaves, or those that have interesting pink/orange leaves, to help brighten up a shady part of the play area.

however, most of my searches online seem to only be able to find seed sources for purple-leaved heuchera, or some dark green leaved ones.

Am I missing something? Is it that these are still protected varieties and they only release them as plants rather than seed? that they are hybrids that only come true from cuttings and there is no hybrid seed?

If you know of a source for good heuchera seed, I'd love recommendations! If I'm on a hopeless search, I'd love to be set straight. Thanks!