<P> In very cold winter areas below zone 6b, cold hardy palms have been cultivated by partially (or completely) covering plants with mini-green house coverings and wraps . Some garden enthusiasts in severe cold winter areas have gone as far as heating the interiors of these winter enclosures . As such, there are occasional reports of hardy palms be cultivated in areas with severe winters with low temperatures below − 18 ° C (0 ° F). </P> <Ul> <Li> <P> Mature Trachycarpus fortunei in Solomons, Maryland </P> </Li> <Li> <P> Trachycarpus fortunei Dusted with snow, in Grand Junction, Colorado </P> </Li> <Li> <P> Rhapidophyllum hystrix In Silver Spring, Maryland </P> </Li> <Li> <P> Chamaerops humilis </P> </Li> <Li> <P> Washingtonia robusta </P> </Li> <Li> <P> Butia capitata In France </P> </Li> <Li> <P> Phoenix canariensis In Melbourne, Australia </P> </Li> <Li> <P> Phoenix dactylifera Planted in Morocco </P> </Li> <Li> <P> Syagrus romanzoffiana Cultivated in Florida </P> </Li> </Ul> <Li> <P> Mature Trachycarpus fortunei in Solomons, Maryland </P> </Li> <P> Mature Trachycarpus fortunei in Solomons, Maryland </P>

What is the most cold hardy palm tree