The USDA Plant Hardiness Zone Map is an essential tool for all landscapers and gardeners, whether professionals or weekend do-it-yourselfers. This simple and free tool will help ensure you select only the correct plants, shrubs, or trees for your region. If you do not follow this guide you risk the health of your plant, and ultimately your time and money.
The Map was designed to show the average annual minimum temperature range throughout the United States, Canada, and Mexico. There are 11 different zones that describe the minimum temperature that can be expected. The zones were divided based on a 10 degree Fahrenheit difference in the average annual minimum temperature.
It is important to understand the zones in order to select a plant that will survive the winter in your region. This is called the plant’s winter hardiness. The winter hardiness of the plant is one of the most crucial factors for the survival and environmental adaptation of the plant. A plant’s hardiness indicates the lowest temperature the plant can sustain and still survive.
Most plants purchased at commercial stores will have their hardiness level indicated on their tag. Determine the Hardiness Zone of the area in which the plant will be located, and make sure the plant’s hardiness falls within the correct zone.
Zone 1 contains areas that see an average minimum temperature below (-) 50 degree Fahrenheit. Example locations include Fairbanks, Alaska and Northwest Territories in Canada.
Zone 2 contains areas that see an average minimum temperature of (-) 50 to (-) 40 degrees. Example locations include Prudhoe Bay, Alaska and Pinecreek , Minnesota.
Zone 3 ranges between (-) 40 and (-) 30 degrees. Examples are International Falls, Minnesota and Sidney, Montana.
Zone 4 ranges between (-) 30 and (-) 20 degrees. Examples are Minneapolis and St. Paul, Minnesota and Northwood, Iowa.
Zone 5 ranges between (-) 20 and (-) 10 degrees. Examples are Des Moines, Iowa and Mansfield, Pennsylvania.
Zone 6 ranges between (-) 10 and 0 degrees. Examples are St. Louis, Missouri, and Lebanon, Pennsylvania.
Zone 7 ranges between 0 and 10 degrees. Examples are South Boston, Virginia and Little Rock Arkansas.
Zone 8 ranges between 10 and 20 degrees. Examples are Dallas, Texas and Gainesville, Florida.
Zone 9 ranges between 20 and 30 degrees. Examples are Houston, Texas and Fort Pierce, Florida.
Zone 10 ranges between 30 and 40 degrees. Examples are Victorville, California and Miami, Florida.
Zone 11 is for annual minimum temperatures above 40 degrees. Examples include Honolulu, Hawaii and Mazatlan, Mexico.
Author Matt Adler is the creator of http://www.laffodils.com, a free website for landscape and gardening advice. See further description ofÂ Plant Hardiness Zones, as well as Maps.