Microclimates, manual control affect planting

Question: What do you say is our planting zone? I got a PlantSmart Sensor for Christmas, and it says we are a 7B, which is way lower than I've read. Just because a website says a tree or plant will be OK for a certain zone doesn't mean it is necessarily, right?

I use both the USDA and Sunset magazine's planting zones for our area. Because we have various microclimates in landscapes, I will normally include one climate zone colder for very exposed microclimates and one climate zone hotter for protected areas with lots of exposure to sun in the winter time and wind protection.

I like Sunset's zones but find them a little bit too narrow at times and too restrictive. That is the reason Sunset went ahead in developing its own and did a fabulous job. On the other hand, the USDA zones are too broad. Very little in this world is perfect, so I use these fudge factors I mentioned to "fudge in" the microclimates.

Frequently, the selection of a plant and whether it will work depends on several things: the microclimate, where you plant it in the yard and how you modify the soil and irrigate it.

Bob Morris is a professor emeritus in horticulture with the University of Nevada and can be reached at extremehort@aol.com. Visit his blog at xtremehorticulture.blogspot.com. For more Bob Morris gardening advice, check the Home section of Thursday's Las Vegas Review-Journal.