This winter is the first time in many years that we were successful at overwintering Pleione orchids in the ground. Up till now, we’ve killed our 9 other attempts. This time, our success was with the cultivar, Pleione ‘Alishan’, a hybrid of Pleione formosana and Pleione limprichtiii.
We’ve done a deep dive to see how much potential there is for these to grow outdoors in our region. Of the 24 Pleione species, native from India into Asia, it seems that 11 of them should be fine in our climate. That list includes P. aurita, bulbicoides, chunii, formosana, forrestii, grandiflora, hookeriana, humilis, limprichtii, pleinoides, and yunnanensis.
The other Pleione species either grow in elevations that are too low or too high. There seems to be more factors at work in determining how well they grow, other than low temperatures, since most Pleiones prefer to grow in duff, as opposed to heavy soil.
Over the next several years, we hope to trial more of both the species and the nearly 450 cultivars, which have parentage that predict their growability in our climate.
I think what kills many of these Pleiones is winter wetness. Did you add additional drainage for Alishan? It doesn’t look like it was planted in the crevice garden.
We planted ours in a very dry site under a large evergreen, so it stays very dry.