Why are itoh and tree peonies so expensive? Are they especially difficult to propogate? I have some herbaceous peonies but recently came across Oochigeas, an Itoh peony. I was shocked at its $60 price tag compared to to 20 to 30 bucks I paid for my other peonies. It's so pretty though!

I think it may depend as to which variety whether they grow quickly or rather slowly. For example, Singing in the Rain is very fast for me, Kopper Kettle very slow.

They are part woody and not as easy to divide as herbaceous peonies - most often needing a saw.

Bartzella, which used to be quite expensive, I have seen at reasonable prices in the past at my local Costco (potted plants, not bare root).

I've also seen large pots of it at local nurseries for the staggering price of $120 (if I'm remembering right).

Seeing something like Bartzella in Costco makes me think they might be tissue culturing them now. I bought a couple (I think about $20-$25 each) and they did flower correctly.

Some herbaceous can be very expensive as well. Just look at some online catalogs and you will see the sticker shock. This one for example, Pastelegance is $199 at Oh my peonies
https://www.ohmypeonies.com/pr...

Another factor is how new it is. Which as daylilly99 said, the supply might be low. Just about everyone wants to be the first to introduce something new before someone else does with something similar. I mainly don't spend high dollars on newer plants that look like cheaper older introduction unless it does something special like blooming longer etc. My DW politely ask the big box stores manager to give her some Itoh peonies that didn't have any price on them late in the season in the mark down area about three years ago. I was shocked when he said go ahead and take all four.