Hi Heidi

Sorry i have not seen this ..before.. But

All my respect for Koen.. but he writes he do not know.. so its ok

But – Kao is from china – In china they have the practice to use the seeds by Kao and also the practice that all other suffruticosa that looks like Kao – they call Kao – this means, if you have got, as we can se more than 1 Kao – they are geneticaly – NOT the same, at all
We have to accept that China – does this way
We in the Western countries – use only a scion from the mother plant ( Kao ) or a section, where you have divided the true tree peony – to call it the name.

Koen names some other suffruticosa..s some of them are from Japan.. where they do different than China – they often only use scions made from the true mother plant – but some of them use also seeds.. like Look alike s calling them the name -the reason why its also importend is – the hardiness

I live in Denmark – and many of the japanese tree peonies are NOT hardy.. enough.. it means they .. just survive.. but the stems die down and they have to start over gain with new stems – some are hardy.. some are not – maybe we could make – a site.. for this

A site where we all could write the name and then our zones for hardiness and how they survive

As Koen also writes..some of the tree peonies from China.. are not hardy in places where the temperature goes down under minus 10 – and the Chinese s it not aware by this

But you Kao.. is not to find geneticaly – But if it survives.. grow it and enoy it.. se if it sets seeds.. or have fertile pollen.. and try to cross with it – and let us know.. how they perform for you