You can probably create a support with bamboo stakes and twine, the green of the stakes would blend in to the plant. Most peony supports are made to be put down when the peony just starts growing for the season. There is a new one out that I want to try called Peony Pal, that one has a swirl top that kind of winds into the erect peony, just not sure it that one would be big enough for your mature plants!

HuMan, there is some excellent information at the link below. Be sure to check the section about Disbudding. Removing the side buds will produce a larger main bloom plus cut down on the weight\flopping issue. I've had good luck with the green bamboo stakes mentioned by Liz. You can find them at most big box stores. They come in different lengths, 25 in a pkg.

Here is a link that might be useful: Planting & Care

This is very helpful - we love the plants and want to do what is best for them. Thank you so much for taking the time to reply.