Plant hardiness zones shift; conditions average 5 degrees warmer

ETTRICK—Just in time for spring, the U.S. Department of Agriculture has released an updated Plant Hardiness Zone Map for the country.

Gardeners and farmers across the nation are looking at growing conditions that are an average of 5 degrees warmer, according to the map. The zones reflect the average annual extreme minimum temperatures between 1976 and 2005.

“This is a good thing for people to know about,” said Andy Hankins of Virginia Cooperative Extension at Virginia State University. “Right now everyone’s looking at seed catalogs, deciding what fruits and vegetables and even flowers to purchase for this year, and this is very important information.”

The new hardiness zone map is the first update in 12 years.

“It’s very important to be accurate with this information,” Hankins said. “When you really think about what crops are affected by winter hardiness, the first ones that come to mind are the fruits. Apples, peaches and especially small fruits like blackberries and blueberries for example. Certain apple varieties have to have enough cold weather to even fruit. We cannot grow Macintosh apples in Florida, for example.”

Hankins said he’s already seen some gardeners shift their varieties and planting times to reflect the slightly warmer climate conditions of recent years.

“The date of average last frost has been mid-April for decades in Central Virginia, but I’ve seen people setting out sensitive crops earlier and earlier in recent years,” he said. “This information is important for new farm crops like edamame as well, which needs a longer season to mature. This could make it possible for us to grow all sorts of new crops and varieties in Virginia. Of course, other crops could drop off. Some cut flowers, like snapdragons, need cooler weather conditions.

“But that’s what this issue really comes down to—gardeners and farmers need this information to make careful selections of crops and varieties to ensure success.”

The new Virginia plant hardiness zones can be viewed online at planthardiness.ars.usda.gov/
PHZMWeb, and information from the USDA’s Agricultural Research Service about how the zones were determined is available at planthardiness.ars.
usda.gov/PHZMWeb/AboutWhatsNew.aspx.


Contact Hankins at 804-524-5015 or Norm Hyde, VFBF communications, at 804-290-1146. 


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