How new plant hardiness maps affect Central Texas
Add Axios as your preferred source to
see more of our stories on Google.
The first "plant hardiness" map published in over a decade shows a warming shift across Central Texas and most of the rest of the country, a change that may affect plant choices for gardeners and growers.
Why it matters: The U.S. Department of Agriculture Plant Hardiness Zone Map is a kind of bible for farmers and gardeners, helping them understand which plants can thrive in their area — and when to plant them.
Catch up quick: The map was last published in 2012, based on 30 years of average annual low temperatures between 1976 and 2005.
- The new map — showing the coldest average temperatures have crept up about 2.5° F across the U.S. — taps data from 1991 to 2020 and information collected from over 13,000 weather stations.
- That's nearly double the data collection points compared to the previous map — improving the accuracy of the new one.
How it works: The map divides the U.S. into 13 zones, each representing a range of 10 degrees Fahrenheit.
- Each zone is divided further into two five-degree half zones.
Zoom in: Central Texas didn't see enough of a jump for gardeners to drastically change which plants they're growing, according to Daphne Richards, Travis County's horticulturist with the Texas A&M AgriLife Extension Service.
- "I would urge people to have caution, and I still would not encourage people to plant tropical species" like citrus trees or hibiscus, Richards told Axios. "We're still going to have a high potential for one of those (cold) outlier events that is just going to snap everything overnight."
Yes, but: Warming temperatures in Central Texas have shifted when gardeners can plant vegetables.
- "It used to be that I would tell people: 'Don't plant them out until about April 1.' Now you can reliably put them out probably mid-March," Richards said.
Between the lines: Many factors influence whether a given plant grows successfully or not, including light, soil moisture, humidity and exposure to the elements.
- It's important to analyze the shade, sunlight and other climate factors before you add a plant to your yard, Richards said.
- The USDA recommends consulting with local producers, nurseries or master gardeners for area-specific growing advice.
The bottom line: You don't need to start changing which plants you're growing — thriving plants will likely continue to grow successfully.