Hotter US Leads USDA to Update Plant Zone Map

The U.S. Department of Agriculture (USDA) has released a new version of its Plant Hardiness Zone Map (PHZM), which shows that Lakeway and the Austin area have moved from USDA hardiness zone 8b to 9a. This means that the average annual minimum temperature in Austin has increased by 5 degrees Fahrenheit. Type in your zip code to see how the change has impacted your specific area.

The PHZM is a guide for gardeners and landscapers to help them select plants that are likely to survive in their area. The map is based on 30-year averages of the lowest annual minimum temperatures at specific locations. The new map uses data from 13,412 weather stations, compared to 7,983 stations that were used for the 2012 map.

The shift to a warmer zone is due to a number of factors, including climate change, urbanization, and changes in agricultural practices. Climate change is causing the average global temperature to rise, which is leading to warmer winters in Austin. Urbanization is also contributing to warmer temperatures in Austin, as concrete and asphalt absorb heat during the day and release it at night. Changes in agricultural practices, such as the use of irrigation, can also affect local temperatures.

The shift to a warmer zone means that Austinites can now grow a wider variety of plants. Some of the plants that were previously considered borderline hardy in Austin, such as citrus trees and bougainvillea, should now thrive in the city. However, some plants that are sensitive to heat, such as azaleas and camellias, may not do as well in the warmer climate.

Here are some tips for gardening in Austin under the new USDA hardiness zone:

Choose plants that are recommended for your new zone.
Water your plants regularly, especially during hot and dry periods.
Protect your plants from frost and extreme heat.
Use mulch to help regulate soil temperature and conserve moisture.

The new USDA hardiness zone map is a valuable tool for gardeners and landscapers in Austin. By understanding the new zones, Austinites can select plants that are likely to thrive in the city’s changing climate.

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