As gardeners, most of us came to believe that palm trees were limited to the far southern tier of America because that was where all of our encounters with the plants have been. From the tall Coconut and Royal Palms of Miami to the luxuriant Canary Island Date Palms of Beverly Hills, we associate palms with leisure, luxury, and most importantly, nice weather. What many fail to realize is that there are many species of palms that proliferate in areas as far north as zone 6, allowing gardeners in these areas to create a jungle island setting in their own yards.
The hardiest species of palms is the Needle Palm (Rhapidophyllum hystrix), which can withstand temperatures as cold as -20F. The plant is slow growing and develops a short, fat trunk covered in long, sharp needles over time. It is palmate, meaning it has fan-shaped fronds, rather than pinnate (meaning feather-shaped fronds) and has beautiful, deep green fronds. Being cultivated as far north as the Connecticut shoreline, this species is a proven winner in the hardiness department. It can get as large as 8 feet tall by 8 feet wide, so plant accordingly. When combined with annuals such as Canna, the palm is the perfect exotic touch for any poolside bed in zones 6 through 9.
Another amazingly hardy species of palm is the Dwarf Palmetto (Sabal minor). This one is hardy to -10F and has also been successfully grown as far north as southern Connecticut and Long Island. Unless planting the "var. Louisiana" variety, do not expect the plant to develop much of a trunk at all. Its lack of trunk is actually one of the main reasons the species is so hardy; it also the growing point of the palm (where fronds emerge) to remain subterranean and thus better insulated from the winter chill. Like the Needle Palm, this plant is also palmate. Unlike the Needle Palm, however, its fronds can take on a beautiful blue-green powdery hue. This one usually ends up no more than 6 feet tall by 4-5 feet wide, but specimens as tall as 12 feet have been documented. The Dwarf Palmetto is reliably hardy in zones 6b to 10.
Though both of the incredibly hardy palms mentioned above are fully hardy in zone 6 once established, they may need a little winter protection in the northern-most fringes of their adaptable ranges for their first few seasons in the ground. For this kind of protection, a pile of dry leaves enclosed by chicken wire or wire fencing on top of and around the palm will often suffice to guarantee the plant sails through winter with flying colors. Due to increasing popularity, these species have become more readily available in zone 6 areas. Check your local garden center today and see if you can get going on tropicalizing your yard!