Gardeners and farmers across the U.S. look to plant hardiness zones for guidance ... and invasive species. Each zone spans a 10°F range in the 30-year average of annual coldest temperatures.

with zone 9 ranging between 20 to 30 degrees Fahrenheit and zone 10 ranging between 30 to 40 degrees Fahrenheit, says FastGrowingTrees. When choosing plants for gardens, plant tags and catalogues ...