I'd say it died instead of rooting. Sorry for that. I've rooted a few things, but I am not very patient. Maybe someone with more knowledge will give you advice. Was it in a warm location? It was moist, but not in standing water?

yes, it was kept warm and moist.

Just saw your post....I root heucheras all the time. I just pull a piece off as far down as possible and stick it in the garden and water it everyday for 2 or 3 weeks, then keep it fairly moist if it doesn't rain.

This spring. I thined my palace purple. I stuck one stem in a pot. Its growing!

You need a piece of stem, not just leaves. I find them easy to root in potting soil or in the garden.