At 05:15 PM 7/30/2004 -0700, Jane McGary wrote: >It's [Paeonia lutea] definitely hardy to zero F or a >bit below. Yes, I think that has been known for a long time. But what about the form known as ludlowii? I don't think it is as hardy. Let me tell you a bit more about the plant which grew here, in particular about the way it reacted to winter here. I mentioned that each year it put up several stems in the 3' - 4' range. What I did not mention is that, with one exception, not one of these stems kept a terminal bud through the winter. (The plant did not form terminal or axillary buds like those of garden tree peonies; such buds as there were, were obscured by the petiole base.) In fact, the growth of this plant was very similar to that of the less wood-hardy forms of Hydrangea macrophylla: the plant was always root hardy, but it always lost lots of wood each winter. Each spring the old stems would sprout out somewhere along their length and then make comparatively prodigious growth (compared to that of typical garden tree peonies). Only once, after a very mild winter, did the stems survive the winter to their tips. I thought that would be the year I finally got flowers. But no, all I got were progressively more gawky stems. During most recent winters here the temperature has stayed above zero degrees F. So, as we have seen with so many other plants, a minimum temperature rating is not telling us the whole story. Jim McKenney email@example.com Montgomery County, Maryland, USA, USDA zone 7, where Ludlow's tree peony at least lasted longer than Potanin's trollius-like tree peony.