USDA Zone 3a: to -39.9 °C (-40 °F)
USDA Zone 3b: to -37.2 °C (-35 °F)
USDA Zone 4a: to -34.4 °C (-30 °F)
USDA Zone 4b: to -31.6 °C (-25 °F)
USDA Zone 5a: to -28.8 °C (-20 °F)
USDA Zone 5b: to -26.1 °C (-15 °F)
USDA Zone 6a: to -23.3 °C (-10 °F)
USDA Zone 6b: to -20.5 °C (-5 °F)
USDA Zone 7a: to -17.7 °C (0 °F)
USDA Zone 7b: to -14.9 °C (5 °F)
USDA Zone 8a: to -12.2 °C (10 °F)
USDA Zone 8b: to -9.4 °C (15 °F)
USDA Zone 9a: to -6.6 °C (20 °F)
USDA Zone 9b: to -3.8 °C (25 °F)
I grew a Lythrum hybrid in Minnesota. It was not the least bit misbehaved. When I dug it up, it did not regrow from bits of root left in ...Read More
FYI-
Lythrum Quarantine
WAC 16-752-400 - 415
purple loosestrife Lythrum salicaria
wand loosestrife Lythrum vi...Read More
Lythrum salicaria, L. virgatum, and all of their hybrids are responsible for a devastating amount of damage to North American wetlands. A...Read More
This species is considered self-fertile. However, research has shown that sterility occurs only when no wild species are growing in the ...Read More