Re: Yucca hardiness
Posted by David MD zn 7 on 5/7/2015, 1:18 pm, in reply to "Yucca hardiness
I would say Y. rostrata and thompsoniana are hardy if kept dry in zn 7. This means, among other things, not becing covered in wet snow for extended periods of time. (I don't know whether you have powdery snow or wet snow in Hungary)
I lost a couple Y. rostrata and another Southwestern yucca species, Yucca schotti, in the winter of 2013-2014 because they were covered with wet snow for weeks which was also subject to freezing and thawing. I don't think the native ranges get much snow whether powdery or not. And even if similar orders of magnitude of snow fall occured in the montane SW US, it would have mostly evaporated instead of melted and the plants would have been able to dry out. I was once in Colorado in September and went to the mountains to hike, we had to turn back because 4-5" of snow had fallen that morning. The next day we went back, and the snow was completely gone AND the ground dry enough to hike without getting any mud on my boots. Remarkable but with air so dry it just disappears during the day.