Great to have you join the dialog here.

The following is a rather strict stance portrayed by authoritative sources. Adventitious buds on roots is dependant on the parentage of the plant the root came from. It is generally thought that pure Lactifloras do not cast adventitious buds. The adventitious buds seem to be more prevalent on some of the other species and hybrids which include these species. If by Chinese herbaceous peonies you mean cultivars that are currently coming out of china then they will be purely lactiflora and should not cast adventitious buds.

My own experience comes from grafting of tree peonies onto herbaceous rootstock. I always look for Lactiflora rootstock for understock. It seems that an awful lot of the supposedly pure Lactiflora roots end up sending up herbaceous stems after 3 or 4 years. Of course if you just bury roots they wont survive for 4 years in the ground so they don't have time to generate adventitious buds.

I have planted blind roots of Salmon Sunset and almost every root sent out a bud by the next year. The buds come from the strangest places. One would think it would be cast near the proxal end of the root; the end which originated nearest to the crown of the plant it was a part of. The roots of substantial size cast buds on the side generally nearer the small end of the root and never more than one bud per root.

As a disclosure I have been told repeatedly that I should refer to the roots as adventitious and not the resulting buds. It just seems more natural for me to state the resulting buds as being adventitious. I say 'a root cast an adventitious bud' rather than saying 'an adventitious root cast a bud'.

Leon