I have been growing them from seed in many batches. I only started out with a few the first time around back in summer of last year where I got a few to germinate, and then I planted more this spring as well as this fall in random locations around my flower beds.
Here's how they look when they germinate. It usually takes a warm period to swell up the seeds followed with a cooler period to germinate them, and then another dormancy cycle over winter to cause them to sprout their initial leaf in the spring.
These guys are the seedlings that sprouted this spring. I made a mistake of transplanting some of them over the summer before they went dormant which killed off some of them, however with the ones I have remaining, I have learned that the best time to transplant would be in the fall when they go dormant.
Notice how there are already 2 extra little buds at the bottom which might eventually become additional stems once this plant puts on some size.
Notice how this seedling seems to harden within a few weeks as it is storing more and more energy in preparation for some more impressive growth the following year.I believe full sun is the best for getting these guys to grow as fast as possible.
Here's a few photos of kinshi, a yellow flower tree peony that I bought last year which has grown slowly, and hasn't made a flower bud until now.
I have also done a plant trade with cricket hill gardens which specializes in tree peonies in order to expand my collection. All of these have been planted in the open so they have plenty of room to grow, and for the grafts, they were planted pretty deep to ensure that tree peony roots can sprout. The tree peony part needs to produce it's own root system so that it no longer relies on the herbaceous root for energy.
Here's a picture showing that each of them having 5 feet of space which allows them to get nice and big.
Here's my tree peony from back in 2009 when it was still alive. This TP thrived for about 4 years as it lived off of the herbeceous root failing to produce it's own roots as it was not planted deep enough. In 2010, the growth was severely weakened and it eventually dried up as it never took root. The only way for grafted plants to survive is to produce their own root system and stop relying on the nurse stock. I could have dug it up back in 2010 and planted it sideways to save it, but this was a hard lesson learned.