While in Kansas, just south of Kansas City, I wintered Manfreda maculosa for two years outside unprotected, but fairly dry. During these two winters it took temperatures into the negative single digits. The two survivors of the brood from Alplains seed (?) came with me to TN where they are completely content in the garden even trying to remain evergreen down to 7F this past winter.
Manfreda virginica, from all the locations I have collected it, have proven hardy in Z5 Kansas, handling temperatures to -10F. All mine are sending up spikes now.
Aaron Floden
Knoxville, TN
On Wed, 6/10/09, Tony Avent <tony@plantdelights.com> wrote:
The only manfreda that I know of which is hardy north of Zone 7b is M.
virginica, which has a wide range. I was in southern Minnesota last
week and saw one that has grown well there for many years. Of the
xMangave's, xM. 'Bloodspot' is the least hardy since A. macroacantha
was a parent. Next is xM. 'Macha Mocha', which is a Zone 8 plant, using
A. celsii. Our unreleased hybrids used A. salmiana v. ferox x Manfreda
jalisciana, both solid Zone 7b plants. I would rate both Polianthes
tuberosa and P. gemniflora also as Zone 7b plants, so we don't have any
hybrids yet that will survive north of the Mason-Dixon line. Jon is
slighter colder than we are, so he may have found some of his hybrids
that can take Zone 7a temperatures. Adding A. polianthifolia to the mix
is brilliant since it got no damage here this year at 9F. That being
said, the work continues.