Polianthes and Manfreda crosses--hardiness issues.
Tony Avent (Tue, 09 Jun 2009 15:34:44 PDT)

Adam:

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.

Tony Avent
Plant Delights Nursery @
Juniper Level Botanic Garden
9241 Sauls Road
Raleigh, North Carolina 27603 USA
Minimum Winter Temps 0-5 F
Maximum Summer Temps 95-105F
USDA Hardiness Zone 7b
email tony@plantdelights.com
website http://www.plantdelights.com/
phone 919 772-4794
fax 919 772-4752
"I consider every plant hardy until I have killed it myself...at least three times" - Avent