That should be a viable piece. I would suggest planting it into a 2 gallon pot with good soil, keep it well watered, and after 2-3 months, it should be a good looking plant.

As long as they have buds, and a good amount of tuberous roots, they should be able to send out feeder roots, and turn into nice strong plants.

I've attached the blog showing how I cut up my itoh peonies before planting them which worked great.

Here is a link that might be useful: Cutting up itoh peonies before planting

Will do! Is the tuberous root the whitish part? Also, you buried the red buds, correct?

I will bury them too, but just barely below the surface so that they don't have to struggle to make sprouts.

If you really want to , you could split up the entire clump of peonies you have and get multiple plants however you just won't get any flowers for this year.

Last fall, I split my huge keiko itoh peony into about 30 divisions. Those actually don't need eyes to produce good divisions however most herbaceous roots do need eyes to be viable.