Tips and advice for maintaining your palm trees.

A Quality Plant Blog

Cold Hardy Palms

Robert Pittman  January 10 2009 10:35:05 AM
There are approximately 2500 different species of palms.  The vast majority of these species can't be grown outside the tropics.

Palms that can be grown in zones 6-9 are considered to be cold hardy.  The chart below shows absolute lows.  Average temperatures for a region are of little use when selecting the right palm for your zone.  One night below the tolerance of the palms in your yard will mean certain death.

Palms are monocots.  They have no ability to sprout back from the roots.  If the heart of the palm dies, the whole palm dies.  Clumping varieties of palms like the Fishtail palm (Caryota Mitis), Dwarf Sugar palm (Arenga engleri) or the Areca Palm (Dypsis lutescens) can come back from the root zone as long as the root zone was not killed during the cold event.

USDA Hardiness Zones and Average Annual Minimum Temperature Range
6b
-5 to 0 F  
-17.8 to -20.5 C
McMinnville, Tennessee;   Branson, Missouri
7a
0 to 5 F
-15.0 to -17.7 C
Oklahoma City, Oklahoma;   South Boston, Virginia
7b
5 to 10 F
-12.3 to -14.9 C
Little Rock, Arkansas;   Griffin, Georgia
8a
10 to 15 F
-9.5 to -12.2 C
Tifton, Georgia;   Dallas, Texas
8b
15 to 20 F
-6.7 to -9.4 C
Austin, Texas;   Gainesville, Florida
9a
20 to 25 F
-3.9 to -6.6 C
Houston, Texas;   St. Augustine, Florida
9b
25 to 30 F
-1.2 to -3.8 C
Brownsville, Texas;   Fort Pierce, Florida



Examples of extremely Cold Hardy Palms:
Rhapidophyllum hystrix - Needle Palm
Sabal minor - Dwarf Palmetto
Trachycarpus takil - Kumaon Palm
Trachycarpus latisectus - Windamere Palm
Trachycarpus wagnerianus - Miniature Chusan Palm
Trachycarpus fortunei - Chinese Windmill Palm
Serenoa repens - Saw Palmetto
Nannorrhops ritchiana - Mazari Palm


Know your zone and the minimum temperatures your palms can withstand. Select palms that can handle the worst your area has to offer.

On calm cold nights the coldest area will settle in the low lying areas.  If you are at the base of a low lying area you may be several degrees cooler than higher elevations.  The front of my main field is several degrees warmer than the back.  The distance is is less than a quarter mile from the front to the back of my field.

There are measures that can be taken to protect palms that are planted out of their zones. Measures like providing wind block and canopy are effective.  If your palms are not too tall, covering them with fabric or frost cloth and supplying supplemental heat will help to hold warmth in and keep frost off.  A low wattage lamp will work to provide the heat.  Christmas lights wrapped around the palm can work on calm nights but help much less on nights with winds in excess of 5 mph.

Rob Pittman
www.aqualityplant.com