I can confirm that Ligtu hybrids, psittacinas and modern horticultural hybrids can tolerate unprotected, snowless frost of -11°C for single nights. Unlike the Ligtus, modern hybrids will lose overground growth to late frosts, but usually return soon after. I agree that my mixed winter climate is far more difficult for them than true continental climate would be. The psittacina actually has more problems with my dry summers, it's a really thirsty plant. Am 30.04.2022 um 05:25 schrieb Jane McGary via pbs: > I don't know where this hardiness estimate came from, but I doubt it > extremely. Any alstro that lives where temperatures go this low would > spend the winter under seasonally permanent snow cover. I don't think > they would tolerate freezing at the depth where the tubers and crowns > lie. > > Jane McGary, Portland, Oregon, USA > _______________________________________________ > pbs mailing list > pbs@lists.pacificbulbsociety.net > http://lists.pacificbulbsociety.net/cgi-bin/… > Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> -- Martin (pronoun: he) ---------------------------------------------- Southern Germany Likely zone 7a _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net http://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net>