Plant Hardiness Zones Important

(Hillsboro, MO) Plant Hardiness zones are designed to record the average of the lowest annual winter temperatures at specific locations across the United States. A Horticultural Specialist with the University of Missouri Extension office in Jefferson County, Debi Kelly, says the map has just been updated for growers.

Kelly adds the map shows that over the last 10 years there has been about a 2 degree warmer temperature difference in the winter hardiness zones as their boundaries seem to be moving farther north.