Hardiness zones (also known as gardines zones) are geographical certain, vertically zoned areas on the principle of the average value of the annual minimum temperature based on many years of statistical observations.
USDA hardiness zone is commonly used in USA an uin the world. But also Australian ANGB, UK's RHZ and Canadian PHZ also usedin some countries.
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Know your zone is the first step to gardening. By understanding your USDA Hardiness Zone or Canadian Planting Zone, you can choose plants that can survive and grow year after year in your area. We’ll explain what planting zones are all about, how to use this information, and links to the latest maps.
Each zone represents ten degrees of temperature difference. Each zone is also divided into “a” and “b” segments. These represent five degrees of temperature difference. For example, zone 4 represents minimum temperatures between -30 to -20 degrees F. (-34 to -29 C.). The a and b subdivisions represent -30 to -25 degrees F. (-34 to -32 C.) and -25 to -20 degrees F. (-32 to -29 C.).
If you are new to gardening, you may be confused by some of the terminology associated with plants. For instance, a USDA zone explanation may be necessary. This is a useful system for determining what plants will survive and grow in certain areas of North America. When you understand how these hardiness zones work, you will be able to better plan your garden.
Obviously, not every perennial, shrub, or tree grows and thrives in every climate. When choosing plants for your garden, it’s important to select varieties that can survive and thrive year-round in your area, especially in regions where extreme winter temperatures are normal. The plant must tolerate year-round conditions, such as the lowest and highest temperatures and the amount of rainfall.
Sometimes Hardiness Ratings Include "S" or "W" - What Does This Mean?When listing the hardiness range of a plant, we often "split" the warm end of the range — for example, you might see a plant listed as Hardiness Zone: 3-8S/10W. In this instance, the 3 refers to the "cold hardiness" of the plant—all else equal, this variety should overwinter successfully in Zone 3. The 8S refers to the humid Southeast and the 10W to the comparatively dry Pacific Coast states of CA, OR, and WA—this plant can tolerate Zone 8 temperatures in the South, and Zone 10 temperatures on the West coast. In Northern climates, summer heat is not typically a consideration.
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 complicated; the problem is that the USDA zones are really not sufficiently specific. For example, our nursery in Connecticut is in the same hardiness zone as Taos, NM—a climate that could hardly be more different than ours (gardeners in the west might find the Sunset Climate Zone maps useful). Furthermore, there are innumerable other variables that may determine how a plant fares in a given site. We find that customers, over time, gain a good understanding of which plants do and don't work for them, and that this understanding is much more helpful than a strict reliance on hardiness zone. When in doubt, please contact us—our customer service team is extremely knowledgeable and ready to assist.
Edited by user 22 March 2023 06:19:00(UTC)
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