I don’t know anything about that suffruticosa cultivar specifically. The Chinese and Japanese suffruticosa cultivars are more often than not unregistered with the American Peony Society (APS) which has been the International Cultivar Registration Authority (ICRA) since 1974. If you go to their database you’ll find several more common suffruticosa cultivars like Hana Kisoi, Shima-Nishiki and Shintenchi that are usually also locally propagated and available in both the USA and Europe. But for many of those directly imported from Asia that is not the case. I do hope that will change.
One specific problem is that translation from Japanese or Chinese into Western-style pronunciation differs sometimes slightly and you may sometimes wonder whether it is the same cultivar or not. The image of your suffruticosa says ‘Kao’. The APS registry doesn’t recognize it. But there are also other sources which I occasionally use to find more information (apart from doing a simple google search of course).
The excellent book about peonies written by Martin Page lists several suffruticosa cultivars, one of them being the Japanse tree peony ‘Kaow’. It might well be the same cultivar. If you’re new to growing peonies or want more information about them, I can only highly recommend this book. Page Martin. “The Gardener’s Peony.” Timber Press: Cambridge, 2005, 267 p.
Another source to find more information about peony cultivars from China/Japan is the Ukrainian peony supplier peony.com.ua who lists several of them. You’ll have to use a browser that can translate other languages (chrome for example). If I search there I end up with Kao Hua Wang, the images also resemble yours, so there’s a chance it’s the same cultivar. And this is what it says about it:
Japanese tree peony Kao – Hua Wang .
The variety was introduced by Mr. C. Watanabe on the Japanese island of Daikon-jima in 1931. This is a fairly easy to care for a variety of Japanese tree-like peonies, which is characterized by a variety of shades, a pleasant aroma and the splendor of flowering.
The flowers are large (20-25 cm), with a vertical arrangement. Petals of reddish-pink shade. Can be completely painted in pink or purple colors. Very contrasting golden core.
Flowering occurs in the middle of the season. Prefers the space around itself, as it can grow nearly one and a half meters.
Kao-Hua Wang is growing very vigorously and can reach two-meter high at the age of 8-10 years.
Frost resistance is very good (it withstands frost below -30 ° C).
Then there is also the tremendously interesting peony site of Carsten Burkhardt which lists countless peony cultivars at http://www.paeon.de with your ‘Kao’ also being in his database (it lists far more than the registered ones). Sometimes written as ‘Kaoh’, ‘Kaow’ or ‘Kaou’, but all referring to the same cultivar.
So, I hope this does help you somewhat 🙂
All the best,
Growing peonies for cutflowers in Belgium. Also hybridizing them.