Q: I am receiving a lot of nursery catalogues and all of them end the plant description by giving a zone designation. What does this mean?

A: The “zone” designation in nursery catalogues refers to “USDA Plant Hardiness Zones.” The Web site is www.usna.usda.gov/Hardzone/ushzmap.html .

There are 10 planting zones in the United States and each zone indicates a 10 degree Fahrenheit difference in the average minimum yearly temperature. A quick look at the hardiness zone map shows that elevation and distance from the equator affect the temperatures in the U.S.

Warmer areas have higher numbers. Southern Florida is in zone 10, where tropical plants can be grown outdoors, year-round. (more…)