01 of 07
Map for Growing Zones for the Northeastern U.S.
Growing zones (also called "planting zones") are intended to be taken as advice, not gospel. There are so many microclimates (both natural and manufactured ones) that you really cannot say definitively that a plant of borderline hardiness in your area will or will not grow for you until you have tested it. If you do not know what a "microclimate" is (or how to create one), see the end of this article (Page 7).
For purposes of the USDA planting zones, the meaning of "Northeastern" is somewhat expanded beyond how it is used in everyday speech. It does not consist simply of the New England states and New York. Rather, it extends south to Virginia and West to Michigan.
Massachusetts, alone -- a relatively small state, in terms of territory (and occupying an especially narrow band of land North to South) -- contains five different growing zones (3-7). The northern reaches of Michigan, New York, Vermont, New Hampshire and Maine include some of the coldest patches in the continental U.S.
Browse through the growing-zone maps on the following pages until you find the one that represents your own U.S. region.Continue to 2 of 7 below.
02 of 07
Growing Zones in the Southeastern U.S.
Within the confines of this region, gardeners will encounter primarily growing zones 6-10. The extreme southern tip of Florida, however, is one rank higher. As is the case with the other regions, rank shoots down precipitously as elevation rises -- a highly relevant factor, since this region is home to the Smoky Mountains, etc.
Gardeners in the Southeast are often challenged by soils with excessive clay. If you face this challenge, in addition to applying soil amendments, you may wish to consider selecting plants that tolerate clayey soil.Continue to 3 of 7 below.
03 of 07
Growing Zones in the South-Central U.S.
Dominated geographically by Texas, this region is subject to extremes in climate. Areas along the Gulf Coast tend to be hot and humid. The Texas Panhandle is hot and dry, as anyone who has journeyed through the area on a historic Route 66 trip well knows (click the link to see photos that provide a small taste of what the region looks like).Continue to 4 of 7 below.
04 of 07
Growing Zones in the Southwestern U.S.
The trip alluded to on the prior page takes one through parts of this region, as well. Its diversity of growing zones is impressive.
California, alone has such a diverse climate that people refer to "Northern California" and "Southern California" as if they were separate states. But it does not end there. The Sierra Nevada mountains and the Mojave Desert are like different planets.
Stark contrasts in climate are the story line for the Southwest overall, ranging from the peaks of Colorado (zone 3) to the burning deserts of southern New Mexico, Arizona and California (zones 10-11). Besides the extremely high temperatures in these southern areas, plant-growers may be faced with the challenge posed by caliche soil.Continue to 5 of 7 below.
05 of 07
Growing Zones in the Northwestern U.S.
Like "the Northeast," the term "the Northwest" enjoys a somewhat expanded meaning when used in connection with USDA growing zones. So if hearing the term conjures up images of the rainy weather characteristic of the Pacific-Coast segment (Seattle, say), you will have to adjust your thinking a bit. For our purposes here, the region extends east to Montana and Wyoming -- hardly known as prime territory for "singing in the rain."Continue to 6 of 7 below.
06 of 07
Growing Zones in the North-Central U.S.
The North-Central region is dominated by cold-weather growing zones (3-5), with only the extreme southern fourth of it offering a more hospitable clime (6-7). The Northeastern part of the area is contiguous with the western Great Lakes.Continue to 7 of 7 below.
07 of 07
What a "Microclimate" Is and How to Make One
By definition, a "microclimate" is the climate of a small, specific place within an area as contrasted with the climate of the entire area, or the "macroclimate." The climate of the entire area is indicated by where a region lies in its USDA plant hardiness zone.
How Microclimates Aid You in Gardening and Landscaping
Now that we have answered the question, "What are microclimates?" let's consider why it is important to learn about them.
Beginning gardeners and landscapers should plant according to the standard growing zones as indicated by the regional maps that the USDA furnishes for gardeners. But growing plants not suited to the climate of your region is sometimes possible if one knows how to exploit microclimates. That is why this is not just an academic issue, but rather helpful and practical information to know. If you play your cards right, you may be able to expand on your typical choices in plant selection.
For example, sunny nooks in your yard that are sheltered from harsh winds and frosts contain microclimates: The temperature there will sometimes remain higher than it does elsewhere in your yard. Such microclimates are excellent for experimenting with plants otherwise considered too tender for your region. Let's say you are gardening in zone 5, and the plant that you would like to grow is supposedly hardy only to zone 6. Try growing it in the microclimate of a sunny, sheltered nook. Success is not guaranteed, but you will have increased the likelihood of the plant's survival considerably.
Such a microclimate can also be a great place in which to harden off plants.
So much for the positive side. On the negative side, the lay of the land in your yard (or in one portion of your yard) may make your plants more susceptible to frost damage. Why? Well, if a piece of land sits down in a low spot (at the foot of hills), cold air may settle there. On nights when you have a frost warning in your area, these are often the spots that get hit worst with the frost. Any tender plants that you have growing there may be damaged by the frost. This is why -- much to the dismay of many a new gardener -- the plants in one area of a landscape may be killed by the very same frost that other plants (in other areas of the yard) survive just fine. Frost damage can be a very localized phenomenon.
Note that microclimates are about more than just ambient temperature and atmospheric conditions. Technically, an area of your yard that enjoys full sun could be considered a microclimate, as could one where full shade reigns. Likewise, spots in the landscape that have a dry soil are treated differently (in terms of what you would grow there) than spots that have a wet soil. But this is common knowledge for gardeners used to what-to-grow-where type questions.
How to Make a Microclimate in Your Yard
What many beginning gardeners are unaware of is the idea that they might possibly be able to get away with growing a plant that -- going "by the book" -- is not sufficiently cold-hardy to grow in their region, by taking advantage of a natural microclimate or creating one of their own (where the temperature will remain warmer than it does elsewhere in the yard). Something as simple as a southerly exposure often provides such a microclimate naturally. But what if you are not blessed with such an exposure?
Well, you can make a microclimate in your yard by taking the appropriate action. Take a look at the picture on the present page. Building a masonry wall around a garden space is an excellent way to make a microclimate. Not only does the wall supply shelter, but it also retains heat and radiates it out later. Here are some other examples of structures that you can erect to create microclimates: