Gardeners use the 2023 USDA Plant Hardiness Zone Map to find perennial plants that will “likely thrive” in your zip code. Check your updated USDA hardiness zone at https://planthardiness.ars.usda.gov.
In South Dakota, mainly the top half of the state is now 4b, hardy -25 to -20 degrees F.
The bottom half of the state is now 5a, hardy -15 to -10 degrees F. The last hardiness map was issued in 2012.
The 2023 national hardiness map is considered more accurate, with about 5,000 more weather stations’ data. The United States and Puerto Rico have 13 zones, each representing a ten-degree change. The new map is about 2.5 degrees warmer than in 2012.
Central Plains and Midwest warmed the most in those eleven years, and the Southwest warmed little, according to an article about the 2023 hardiness zone map in January/February 2024, The American Gardener.
Do we need to change gardening for a warmer climate?
The two-degree increase in change of temperature is enough to impact plants’ natural moisture, while increasing carbon dioxide and erratic weather may affect heat available to plants and light quality.
Jennifer Boldt at the University of Toledo asks questions about crop plants such as tomatoes and soybeans and studies them in a controlled environment. She asks:
“How do different environmental conditions potentially affect how nutrients are taken up by the roots of a plant? What implications does that have for plant growth or the quality of plants being grown?”
She looked at combined environmental conditions to see the impact on plants. With high drought and high carbon dioxide, “plants didn’t take up nutrients as much, so we had lower levels of nitrogen and phosphorus in the leaves.” Lower nitrogen makes the plant less green, grows more slowly, and is less nutritious. See “Growing Plants in a Hotter World” at the USDA link for more about her study.
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