We have compiled this report on the cold hardy palm from both our experiences and those of others around the country. Our hardiness classifications are probably a bit conservative, but be wary of wild claims of palm hardiness beyond these zones. Even a Zone 7 palm will survive a winter in Zone 5 if the temperatures don’t drop below Zone 7 temperatures (0 degrees F). When I hear these outlandish claims, I generally discount them unless the claimant can give me specific low temperatures that the palms endured.

Keep in mind that while forms of palms are selected for particular traits including winter hardiness, the plants are seedlings and each is genetically different. These selections have only an unquantified greater percentage of chances at winter hardiness over one that has not undergone any winter hardiness selection. This is not a guarantee of winter hardiness

In palm hardiness, size matters… small palms are simply not as winter hardy as larger ones. One lesson that we’ve learned well over the years is that in temperate climates, palms need to be planted early in the growing season and planted at a large size. If you are only able to purchase a small size palm (like we sell), grow it as a houseplant until it reaches a larger size and becomes more winter hardy. While we’ll still plant a one gallon palm of some types, most folks recommend not planting anything smaller than a three gallon size in a marginal climate.

If you must plant palms smaller than we recommend, be sure to get them in the ground as early as possible in the growing season. During the winter, much very heavily for the first few seasons until the plants gain some size, at which time the winter mulching can be scaled back.

There are a number of techniques used to push palms beyond their normal limits of hardiness. This includes wrapping the trunks with thick frost cloth, wrapping the trunks with old-style Christmas lights (the ones that gave off heat) or plumbing heat tap during the winter months. Another common technique used to prevent winter damage is to tie the uppermost leaves in a bundle to keep the unfurled spear leaves from getting wet and cold. It’s often not the cold that kills palms, but the combination of wet and cold together.

Other than foliar burn, one of the most common forms of winter damage is spear pull. This is where the new fronds at the growing tip are killed. This damage may not be evident until several months afterwords when the new fronds turn brown, then black. A tug of the unfurled leaves will cause them to separate from the crown. This does not necessarily mean the plant is lost. It is best to removed damaged spear leaves as soon as possible to allow air and light into the crown to prevent rot which can kill the plant. Some folks just make sure that air can get to the crown and that water doesn’t stagnate where the spear was removed, while others drench with a fungicide. If the damage wasn’t too severe, another spear will emerge, usually within 8-12 weeks.

Group 1 Reliably winter hardy in Zone 6a (-10F) once established.

Rhapidophyllum hystrix Sabal minor ‘McCurtain’

Group 2 Reliably winter hardy in Zone 7a (0 degrees F) once established

Sabal minor ‘Emerald Island Giant’ Sabal minor ‘Bear Creek’ Sabal minor ‘Castor Dwarf’ Sabal minor ‘Chipola Dwarf’ Sabal minor ‘Blountstown Dwarf’ Sabal minor ‘Oriental Giant’ Sabal minor ‘Woodville’ Sabal x texensis ‘Brazoria’ Sabal minor var. louisiana Sabal ‘Birmingham’

Group 3 Reliably winter hardy in Zone 7b (5 degrees F) once established.

Sabal etonia Sabal palmetto ‘Bald Head Island’ Sabal palmetto ‘Mt. Holly’ Sabal palmetto ‘Rock Hill’ Sabal palmetto ‘Tifton Hardy’ Sabal sp. Tamaulipas Trachycarpus fortunei ‘Bulgaria’ Trachycarpus fortunei ‘Charlotte’ Trachycarpus fortunei ‘Greensboro’ Trachycarpus fortunei ‘Hayes Stiffie’ Trachycarpus fortunei ‘Nanital’ Trachycarpus fortunei ‘Norfolk’ Trachycarpus fortunei Taylor Form Trachycarpus fortunei Tennessee Form Trachycarpus fortunei ‘Wagnerianus’ Trachycarpus nanus

Group 4 Reliably winter hardy in Zone 8a (10 degrees F)

Butia capitata Chamaerops humilis var. cerifera Chamaerops humilis Guihaia argyrata Jubaea chilensis Nannorrhops ritchieana Sabal uresana

We hope you have found this series on the cold hardy palm helpful in selecting the best one for your garden.

Source by Tony Avent