Based on the minimum ten-year average winter temperatures, plant hardiness zone maps have been progressively developed, first by the Department of Agriculture (USDA) for the United States and then more or less applied to the rest of the planet. Whilst average winter temperature may be similar, summer heat, duration, humidity, snow cover and even day length is completely different. Though different, we found common variables in certain regions, allowing us to engineer the HZ5® product line for zones 1 through 5 and the HZ10® product line for zones 6 through 10. When planting and growing plants it is very important to know what hardiness zone you are in.… An example, if the plant tag says a plant is hardy in zones 6 to 10 the plant will be an annual for me in zone 5. Zone 1 is the coldest and is subject to frost year-round while Zone 11 is the warmest and completely frost-free. Most hardy plants have a zone rating to indicate where they will survive the winters from year to year. What is the USDA Plant Hardiness Zone Map? This includes necessary cookies to interact with the website, anonymous analytical data, and some third party cookies. By Dr. Leonard Perry, Extension Professor University of Vermont Not all plants are hardy in Vermont. The USDA created a Plant Hardiness Zone Map in 1990 that divides the country into 11 zones, each separated by approximately 10 … Nearly any rose can be grown in Zones 7, 8, and 9. The U.S. Department of Agriculture’s plant hardiness zone map breaks geographical regions into zones based on the average low winter temperatures. Often listed as zones 10 or 11 plants these are tropical plants used frequently as tender perennials, annuals, or seasonal tropical plants to add seasonal color and texture to flowerbeds and containers. Zone 1 is the coldest climate and zone 13 is the hottest. If a rose on our website is marked Zone 7, the coldest zone it is hardy in is Zone 7. HZ5® Fights Cold, Snow, Ice and Worry. The tag on plants contains zone information, saying which zone it grows best in, or you can do an Internet search to find the information. The USDA Plant Hardiness Zone Map indicates the minimum temperatures that plants can tolerate. There is no indication of humidity, snow cover or summer heat. 12 years ago. H5-15 to -10 (5 to 14) Hardy - cold winter : Hardy through most of the UK even in severe winters. Perhaps you learned this the hard way when a favorite shrub or flower didn't make it through the winter. Learn more. Follow. The regions are defined by a 10-degree Fahrenheit difference in the average annual minimum temperature. Question: What does a “Hardiness Zone” mean when I’m buying plants? If you are planning to buy a shrub, perennial or tree, you need to make sure that this new plant will tolerate year-round conditions in your area. For instance, most clematis hybrids are said to be “hardy in Zones 3 to 8.” This statement means anyone gardening i… Hardy plants can live…. For instance, plants that can survive down to 0 degrees are in Zone 7. Using these factors we arrived at ten distinct climatic zones. The zones are not important for annuals since these are plants you would only expect to survive the summer months, or one season. The EGF zones are: H1 ~ Hardy to -20 o C (-4 o F) and below; H2 ~ Hardy to -15 to-20 o C (5 to -4 o F); H3 ~ Hardy to -10 to -15 o C (14 to 5 o F); H4 ~ Hardy to -5 to -10 o C (23 to 14 o F); H5 ~ Hardy to 0 to 5 o C (32 to 40 o F); G1 ~ Requires cool greenhouse protection; G2 ~ Requires heated greenhouse protection. If you ever have any questions on which plants grow best in your hardiness zone or need to know whether a specific plant will grow in a specific zone, a local garden center will be able to help you. This is easily explained by pointing out that the majority of Texas, USA is also a USDA Hardiness Zone of 9. Whilst the USDA system of plant hardiness zones is well adopted across the world, it’s not without its drawbacks. The 1990 hardiness zone map was created based on historical weather patterns. The system of Plant Hardiness Zones was developed by the United States Department of Agriculture and, put simply, is a geographically defined area in which a specific category of plant life is most likely to thrive. Dorset
That is why some plants are hardier than others, even why some cultivars are hardier than others of the same plant. Zone 7a: This subzone has a minimum average temperature of 0° to 5° F. Zone 7b: This subzone has a minimum average temperature of 5° to 10°F. yes, it means that anything zone 6 and up it should survive the winter, in other words zone 5 probably won't survive and zone 7,8,9 it will. When we go to buy shoes, we all know that we have a shoe size, or a size of shoe that best fits our foot. A plant is considered “hardy” if it will survive the winter in that particular zone. But, what is hardiness, and what does it mean to you as a gardener? It may not be the best fit for them to be one zone outside of their recommended hardiness zone and they may not grow as well as they should, but sometimes you make exceptions and take special care of a plant you really want to have. The range of minimum average temperatures for zone 3 is between -40°F and -30°F or -40°C and -34.4°C. Parley
Plants can be described as ‘Hardy to Zone 10’ or ‘Hardiness Zone 10’, but what does this mean for the plant and how does it affect where you can use them? Since the hardiness zone is so important, you may be wondering how to tell which zone is good for which plant. There are two sources to find your climate zone. However, it does have a number of drawbacks, most significantly in not incorporating summer heat levels into the zone determination. If it says a plant is hardy to Zone 6, does that mean UP TO Zone 6, or DOWN TO zone 6? For more ideas ask your local garden center professionals and make sure you follow us on Facebook, Twitter,YouTube, Instagram and Pinterest for other tips and hints. Tulips for example, can be planted in as low as Zone 4. This enables people all across the world to understand whether plants can handle specific areas of the world. For perennials, trees, and shrubs though, be sure to check the USDA zones before you put them in your garden. The US Department of Agriculture (USDA) has divided North America into 13 different hardiness zones based on temperature and climate. Sign up to receive news, updates tips from Bylands in your inbox each week! USDA Plant Hardiness Zones are not a definitive guide but a helpful extra bit of information to use in conjunction with other information such as ‘Indicator Plant Species’, geographic information and local information. It is where that plant is comfortable and can grow the best. These cookies can be disabled in the browser settings. Hardy definition is - bold, brave. Each one is labeled as zone 1, zone 2 etc. Each zone has a 10 degree differential, based on the average minimum temperature of the location, between the previous zone, or, in other words, zone 1s average minimum temperature is 10 degrees colder than zone 2s. Just like you would never want to walk around in a shoe three sizes too small for you, a plant does not want to grow in a hardiness zone that is way outside of its comfort zone either. When you see “Zones 3-7” on a plant tag, what does it mean? Each subzone is separated by 5°F. The same is true with plants. They have a hardiness zone that fits them best. Thank you for any help. Near western coastal areas the influence of the Gulf Stream means that some frost-hardy, and even half-hardy plants can survive the winter out of doors. -10 to -5 (14 to 23) Hardy - average winter: Hardy through most of the UK apart from inland valleys, at altitude and central / northerly locations.