Plant Hardiness Zones Explained (2024)

FAQs

Plant Hardiness Zones Explained? ›

These zone numbers are meant to guide you when selecting plants, ensuring their hardiness numbers are appropriate for your zone. If a plant's hardiness zone is listed as 6a-8b, and you live within one of those zones, then this plant is appropriate for you; it can withstand temperatures down to an average of -10°F.

A plant that is hardy in zone 8 – 10 probably will not survive a zone 6 winter since there is a 20 degree average low difference, but you may find success growing a zone 8 – 10 plant in zone 7, or a zone 7 plant in zone 6.

This means about half of the country has moved into a warmer hardiness zone. Here at home, Albemarle County and much of Central Virginia are now classified as zone 7b, rather than the previous 7a. Elsewhere in the Commonwealth, nearly every city in the Hampton Roads region has moved from zone 8a to zone 8b.

Hardiness zones are based on the average annual minimum temperature in a given area. Each of the map's colored zones is separated by 10 degrees and divided into subzones A and B, separated by five degrees. To determine your gardening zone, type in your ZIP code at the US Dept.

Each USDA hardiness zone has 10 degrees of minimum average temperature difference and is divided into two sections, a and b. Zones 7a and 7b both have a medium-length growing season. Zone 7a's minimum average temperature is 0 to 5 degrees, and Zone 7b's minimum average temperature is 5 to 10 degrees.

Zone 7 encompasses several thousand square miles west of the Sierra Nevada and Cascade ranges, and in the mountains that separate the Southern California coast from interior deserts.

However, especially cold-hardy plants may not survive the summer heat of this region. The Zone 9 map includes the following states: Florida, Georgia, South Carolina, Texas, Alabama, Louisiana, Mississippi, Utah, New Mexico, Arizona, Nevada, California, Oregon, Washington, and Hawaii.

Geranium Rozanne. Hardy Geraniums are without a doubt one of the very easiest plants to grow and they give you so much back. Amazingly floriferous, make excellent groundcover, attractive to pollinators, slug and rabbit resistant, fully hardy, unfussy on soil conditions and not to mention beautiful.

The Plant Hardiness Zone Map (PHZM) is based on the average annual extreme minimum winter temperature, displayed as 10-degree F zones ranging from zone 1 (coldest) to zone 13 (warmest). Each zone is divided into half zones designated as 'a' and 'b'.

So to summarize—a plant listed as 3-8S/10W should successfully overwinter in zones 3 or warmer, tolerate humid heat up to zone 8, and tolerate dry heat up to zone 10. We realize this is a bit complicated, but the problem is that the USDA zones are not always sufficiently specific.

What does zone 5b mean in gardening? ›

Zone 5: The minimum average range of temperatures is -10° to -20°F. Zone 5a: This subzone has a minimum average temperature of -15° to -20° F. Zone 5b: This subzone has a minimum average temperature of -10° to -15°F.

Zone 6b has a minimum average temperature of -5F to -0F. Zone 6 stretches in a long arc from Long Island and New Jersey, through Pennsylvania, Ohio, Indiana, Illinois, Missouri and Kansas, and then right up through The Rockies into Washington State – with colder zones at higher altitudes and warmer zones at lower.

Zone 4 plants can withstand minimum chill temps from -30°F to -20°F. You can find this zone in Montana, Wyoming, North Dakota, South Dakota, Minnesota, Wisconsin, and northern areas of Eastern states such as New York, Vermont, New Hampshire, and Maine.

With freezing cold temperatures in the winter and warm summers, USDA Hardiness Zone 6 gives plenty of plants the balance of heat and cold that they need to thrive.

Cold Hardiness zones are based on the average annual minimum temperature in a given area of the country, with USDA Zone 1 being the coldest at minus 50 degrees F and USDA Zone 13 the warmest at above 60 degrees F.

The frigid zone is the coldest heat zone on the earth. It found one each in the two hemispheres. The Frigid zone in the northern hemisphere lies between Arctic Circle and the North pole and in the southern hemisphere between Antarctic Circle and South pole.

The polar climate zones consisting Tundra and Ice cap climates are the coldest winter spots on planet Earth with the temperatures ranging from -20 degrees to -70 degree F. Continent antarctica is found to have the lowest temperatures with Ice cap climate.