Palm Tree source for palm tree types, pictures and care
Cold Hardy Palm Tree Zone Map (Plant Hardiness) Described.

Cold Hardy Palm Tree Zone Map Described

Cold Hardy Palm Trees Species

True Date Palms

Canary Island Date Palms

Texas Sabal Palms

Mediterranean Fan Palms

California Fan Palms

Windmill Palms

Pindo Palms

Sago Palms

Mexican Fan Palms

Queen Palms



Palm Tree Pictures

True Date Palm Tree

Canary Island Date Palm Tree

Texas Sabal Palm Tree

Mediterranean Fan Palm Tree

California Fan Palm Tree

Windmill Palm Tree

Pindo Palm Tree

Sago Palm Tree

Mexican Fan Palm Tree

Queen Palm Tree


Palm Trees Care, Resources

Palm Tree Information

Basic Palm Trees Needs

Cold Hardiness Zones Description

Cold Hardiness Zone Map

Palm Trees Care Environment

Palm Trees Care Pruning

Palm Trees Comparative Summary

Frequently Asked Questions

Palm Trees Discussion Boards

Web Site Links




Archived Palm Trees Information

True Date Palm

- General

- Detailed

Canary Island Date Palm

- General

- Detailed

Texas Sabal Palm

- General

- Detailed

Mediterranean Fan Palm

- General

- Detailed

California Fan Palm

- General

- Detailed

Windmill Palm

- General

- Detailed

Pindo Palm

- General

- Detailed

Sago Palm
Mexican Fan Palm



Cold Hardy Palm Tree Zone Map Described

Introduction to the Plant Hardiness Zone Map

This map supersedes U.S. Department of Agriculture Miscellaneous Publication 814, "Plant Hardiness Zone Map," which was revised in 1965.  This 1990 version shows in detail the lowest temperatures that can be expected each year in the United States, Canada, and Mexico.  These temperatures are referred to as "average annual minimum temperatures" and are based on the lowest temperatures recorded for each of the years 1974 to 1986 in the United States and Canada and 1971 to 1984 in Mexico.  The map shows 10 different zones, each of which represents an area of winter hardiness for the plants of agriculture and our natural landscape.  It also introduces zone 11 to represent areas that have average annual minimum temperatures above 40 F (4.4 C) and that are therefore essentially frost free.

Back to top

How to Use the New Map

Zones 2-10 in the map have been subdivided into light- and dark-colored sections (a and b) that represent 5 F (2.8 C) differences within the 10 F (5.6 C) zone.  The light color of each zone represents the colder section; the dark color, the warmer section.  Zone 11 represents any area where the average annual minimum temperature is above 40 F (4.4 C). The map shows 20 latitude and longitude lines.  Areas above an arbitrary elevation are traditionally considered unsuitable for plant cropping and do not bear appropriate zone designations.  There are also island zones that, because of elevation differences, are warmer or cooler than the surrounding areas and are given a different zone designation.  Note that many large urban areas carry a warmer zone designation than the surrounding countryside.  The map-contains as much detail as possible, considering the vast amount of data on which it is based and its size.

Back to top

How the Map Was Started

Every plant can adapt to a range of environments.  Gardeners have learned through experience where the great variety of landscape plants can be grown.  Over the years many schemes have been proposed to help gardeners locate those environments when they introduce new species, forms, and cultivars.  The pooling of many of these schemes culminated in the development of the widely used "Plant Hardiness Zone Map," under the supervision of Henry T. Skinner, the second director of the U.S. National Arboretum.  In cooperation with the American Horticultural Society, he worked with horticultural scientists throughout the United States to incorporate pertinent horticultural and meteorological information into the map.

The elements of that map were:

Zones.  The contiguous United States and southern Canada were divided into 10 zones based on a 10 F (5.6 C) difference in average annual  minimum temperature.

Winter Hardiness.  Survival of landscape plants over winter was selected as the most critical criterion in their adaptation to the environment.

Classification The zone ratings were intended to indicate excellent adaptability of the plants.   Many plants may survive in warmer or colder zones.  Usually, mere survival does not represent satisfactory performance.

Interactions With Other Environmental Factors.  Many other factors may come into play in determining satisfactory growth.  Wind, soil type, soil moisture, humidity, snow, and winter sunshine may greatly affect the adaptability of plants.

Interactions With Cultural Factors.  The way plants are placed in the landscape, how they are planted, and their size and health can greatly influence satisfactory adaptability.

Back to top

Why the New Map was Created

The "Plant Hardiness Zone Map" was published in 1960 and revised in 1965.  Since then, many changes, new interests, and new responsibilities have emerged in North American landscaping:

Changes in Weather We have been losing from our landscapes plants that apparently survived the 1940's to the 1960's.  Many of the hardiness zone classifications of plants are no longer considered valid.  In North America, the ranges of temperature and moisture for the past decade were wider than those recorded for the 1940's through the 1960's.

Introduction of New Elite Forms Our landscape industry has worked with plant explorers and breeders to introduce many new forms of traditional plants that are adapted to a wider range of environments than the older forms.

Scope.  The continental United States is contiguous with Canada to the north and Mexico to the south.  We share more than a common border-we share indigenous plants and many introduced plants that can be grown successfully.  We needed to expand the scope to include the whole of North America.

Back to top

How the New Map Was Created

The average annual minimum temperature data were analyzed for Mexico, the United States, and Canada.  Of 14,500 stations that measured temperature during the period of interest, almost 8,000 could be identified by latitude and longitude and by a valid average annual minimum temperature (i.e., an average based on at least 10 years of data).  Data from only the latter stations were used in the map.  The data were archived by Servicio Meteorologico Nacional (Tucubaya, D.F., Mexico), the National Climatic Data Center (Asheville, NC), and Environment Canada - Canadian Climate Centre (Downsville, Ontario).  Temperature data were compiled and maps prepared under contract with the Meteorological Evaluation Services Co., Inc., 165 Broadway, Amityville, New York 11701.   The map is an Albers Equal Area Projection.  Standard parallels of 29.5 , and 45.5 , were used to generate the map of the three countries.  The map was computer generated by latitude and longitude.  Because of the large area involved, it is not possible to draw one map that is accurate for all of North America.  The part representing the United States has the least distortion.  The Agricultural Research Service proposes to periodically evaluate weather data and issue updated maps as necessary and appropriate.

Back to top

The 2003 US National Arboretum "Web Version" of the USDA Plant Hardiness Zone Map
USDA Miscellaneous Publication No. 1475, Issued January 1990


Cold Hardy Palm Tree Zone Map Described

Sun Palm Trees