Microclimates: Pushing the Zone

Looking through catalogs, you may find some plants you love, but they are for a warmer zone than you’re in. Should you get the plants anyway?

It depends on your microclimate. Although the USDA map shows climate zones in wide swaths, there are small areas—maybe even within your yard—that are warmer or colder. For instance, an area out of the wind (like a courtyard) is warmer than an area where the wind comes sweeping down the plains. An area with a lot of stone or pavement is warmer than one without. The other day, I passed a building in Denver with a stone planter out front next to a wide sidewalk. Rosemary, a zone 6 plant, was growing in the planter in a zone 5 region, and was so large that it must have been growing there for years.

The area next to a building or house is usually warmer, too. My parents grow Zephirine Drouhin, a zone 6 rose, next to their house, as do I. The canes on this wonderful old garden rose are several feet long. If you want a plant next to your house, don’t plant it too close. Watering next to the foundation can flood your basement, and someday, you may need to paint or put new siding on your house.