Until they become acustomed to the bright sun you might want to provide temporary shade such as a lattice placed to block the sun after Noon. It must be wonderful to have a tp that old. Somewhere in my books I have an article about tp's in England before WWII and how large they were. Could you describe your plants or post a picture.

Thanks Maifluer. These two tree peonies we inherited when we bought our 1922 bungalow. I date them from neighbors and "old timers" who have been here a long time. They could be older, I just don't know.
One is pink,double,about three feet plus. It tends to bloon earlier than the white and not as prolific. The other, the white, is outstanding. about four feet. Last year I had 32 (yes I counted) blooms all at the same time. The blooms are double that open and expose the bright gold and red of the stamens.
It will be very upsetting to lose them.
jim

Jim,
All of my tree peonies are growing in full sun and we have very hot summers here. Tree peonies don't seem to mind wheather they are in full sun or part shade. However the flowers do seem to mind. The extra heat will cause the flowers to age faster and they just will not last as long. Worse than full sun is the blasted wind that I have out here. Hard wind can really make blooms look ragged after just one day.

LP

I have two tree peonies growing on the very sunny, western side of my patio with a wooden lattice behind them. They have been growing well since I moved them there about 5 years ago. Perhaps you could plant another fast growing tree or shrub to provide shade, and put up some lattice as a temporary measure.