United States Hardiness Zones

The ‘USDA Plant Hardiness Zone Map’ outlines the different zones in which various types of trees, shrubs and plants will most likely survive. It is based on average extreme low temperatures over a 30 year period—not just the lowest temperature ever reached at any given time. Gardeners should understand that this map is a guide only – not a guarantee of gardening success, as climatic conditions are constantly changing and there are many other factors that can affect the success and failure of plants.

This map is an excellent starting point however if you are wondering if a certain plant will generally over-winter (survive the coolest temperatures). As well as using this map for reference, we recommend consulting other gardeners who have ‘hands-on’ experience of weather and gardening patterns in your area.

Along with year-to-year variations in weather, microclimates can also play a role in determining the right plants for your garden. Microclimates, which are small areas of varying weather conditions within larger zones, can be caused by local geography of the area such as hills and valleys as well as variations of solar and wind exposure. Even buildings and pavement in urban areas can create relatively small microclimates that can potentially produce different gardening results.