Dear All, I have my two cents on this topic. Here in old gardens of (one time) noble people is not difficult to find specimens of tree peonies, often century old in not more. I have seen a plant almost 2m tall of a popular variety (Duchesse de Mornì) which is an old French hybrid. I have some of these too and they flower reliably every year. They have a very short 'window' of growth, just in later Frebruary and March. After then, all is done and the plant won't put any other leaf till next year. A couple of friends grow other tree peonies, like the mentioned Souvenir du Prof. Maxim Cornù and Prince of Troubeskoy and a few others I don't remember now. There's a famous nursery in French, hybridizing tree peonies from 150 years I remember. In Italy there's also a specialized nursery, inland Rome, which has one of the largest selection of tree peonies worldwide. Also, in Rome BG's they have a collection of those Chinese tree hybrid John Ingram mentioned ( silver drops of moon crying for the dying dragon with red coral blood etc etc :-) ) Paeonia mascula is native here, but only one time I was lucky enough to meet it and since then I have no more reloacted it, probably digged from a sunday's gardener (to use still a polite word). I have tried two times lactiflora hybrids, sold in the bulbs catalogues in spring, but they have always died after two or three years for the summer heat. that's all Angelo Porcelli south of Italy - Mediterranean to desert-like climate !