Pick the Perfect Plant

August 20, 2012

Most all gardeners are aware of the USDA climate zone map for the United States, but did you know that there is also a heat zone map? I didn’t know about it until the other day when I was looking for the climate zone map on Google and found the heat zone map, too. It was compiled by the American Horticulture Society (AHS) to show the number of days per year that the temperature is above 86 degrees for all areas of the US. This is a great new tool for gardeners to use to ensure the plants they choose will thrive in their area.

By using both maps, it will be easier to pick the plants that will do well in your garden. According to the climate zone map, most of this area in in zone 6a with the coldest temperatures normally between -5 and -10 degrees. The heat zone map puts this area in heat zone 7 with 60 to 90 days of temperatures above 86 degrees per year. In my opinion, that’s 60 to 90 days too many, but that’s beside the point. The point is that by knowing how hot the summers are in your area, you can better choose plants that will thrive.

Just because a plant is winter hardy where you live doesn’t mean that it will survive the summer heat. For instance, I have tried many times to grow Irish Moss and Corsican Mint. These are groundcover plants that are supposed to be winter hardy to zone 5. They do really well for me in the spring; however, when the summer heat hits, they both shrivel up and die. I found out that they don’t like the heat. Usually, I keep the cold tolerance of plants in mind when I’m shopping for my landscape, but now I know to take the heat tolerance into consideration, too. You can check out the map at http://www.ahs.org/publications/heat_zone_map.htm. Then, click on "Downloadable Heat-Zone map."

Heather C.
Lee's Summit Branch