What is the USDA Hardiness Zone Map?

Understanding the hardiness zone map is the best way to make sure that you purchase and plant the correct plants for your area. This map is going to tell you what the average annual temperatures are your part of the country. This will make you better equipped to make wise plant choices.

The USDA Hardiness Zone Map is based on a study of the average annual minimum temperatures recorded by 14,500 weather stations all across North America. It includes zones 1-11. The higher the number, the higher the annual temperature is. For example, Key West and parts of Southern California are in zone 10.

Actually, California has another hardiness zone map designed especially for them by Sunset magazine. Just because they are in zone 10, doesn't mean they are able to grow everything from zone 1-9. Some plants, especially By purchasing the right plant for the right zone you will save yourself some heartache and money down the road. Your plants will not need so much TLC from you when it comes to watering requirements and pest problems. perennials and bulbs, need to go through a dormancy period in order to bloom.

If you want your plants to do well, keep your zone in mind when you buy your plants. Usually, the plant tag on the plant you are considering will tell you what zone it is best suited for. Also, catalogs and web sites have this information as well.

Microclimates

These microclimates are determined by exposure, elevation, and wind. For example, in the warmer microclimates of your yard, perhaps next to your house, you may be able to grow a few plants from the next zone to your south. Rosemary is a perfect example of this. It is considered a marginally hardy plant in the Mid-South, so if you plant it next to your house it has a better chance to survive.

On the other hand, you may find that most of your yard needs hardier plants than your zone requires. This might be true if you live up on a hill with cooler winds blowing much of the time. You would need to choose a plants from the next zone up for yard.

It will take some experimenting to figure out where the microclimates are in your yard. Just remember that our gardens are always changing. If a plant doesn't seem to like it where you have planted, try another spot if you have the time and energy. Be sure to wait until the plant is dormant for better results.

Factors to consider when purchasing plants.

• Southern and western sides of houses and other structures are sunnier and warmer than northern or eastern exposures.
• Southern and eastern exposures usually are protected from the cold winter winds
• Strong winds can damage plants, by either drying the soil or knocking over fragile growth
• Cold air sweeps down from hills and rests in low areas of the neighborhood
• Your microclimate will change as your trees grow larger or when you add a fence or deck.

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