Selecting Plants For Your Region
While some of our selections are very adaptable and grow well in most of the country, the United States is a land of diverse topography, light levels, rainfall, humidity and temperature. Knowing something about the climate you garden in and choosing plants that grow well in those conditions is the easiest way to have a beautiful home garden.
Once you understand you know the general parameters of your climate, you can think about microclimates or pockets within your garden that have specialized growing conditions. For instance, even though most of your landscape may be sunny, many properties have taller shrubs or buildings which create shade for shade loving perennials. You may also find that although you live in a particular USDA Hardiness Zone, you can grow perennials and shrubs that are listed for warmer Zones because you have areas that are protected from harsh winds or stay warmer from surrounding areas. If you garden in Zone 4 and think you have a microclimate that will support a plant listed for Zone 5, by all means, give it a try.
One resource you can turn to for detailed information on the climate where you live is your county Cooperative Extension office. The Cooperative Extension System is a nationwide, non-credit educational network. Each U.S. state and territory has a state office at its land-grant university and a network of local or regional offices.
Go to http://www.csrees.usda.gov/Extension/index.html to find statewide resources as well as your county office.
Rainfall and Temperature
Rainfall and temperature are the two most important climactic factors to be aware of when selecting plants. The USDA Plant Hardiness Zone Map uses average annual minimum temperature to assign plant hardiness zone ratings to various area of the country. It divides the United States into 11 Zones with Zone 1 being the coldest and Zone 11 being the warmest.
Plants are assigned corresponding hardiness zone ratings based on the lowest temperature they will survive. All the plant descriptions at Great Garden Plants include a USDA Hardiness Zone rating and you should use this as a guide when deciding which plants will grow well in your garden.
USDA Hardiness Zones and
Average Annual Minimum Temperature Range
|1||Below -50 F||Below -45.6 C||Fairbanks, Alaska; Resolute, Northwest Territories (Canada)|
|2a||-50 to -45 F||-42.8 to -45.5 C||Prudhoe Bay, Alaska; Flin Flon, Manitoba (Canada)|
|2b||-45 to -40 F||-40.0 to -42.7 C||Unalakleet, Alaska; Pinecreek, Minnesota|
|3a||-40 to -35 F||-37.3 to -39.9 C||International Falls, Minnesota; St. Michael, Alaska|
|3b||-35 to -30 F||-34.5 to -37.2 C||Tomahawk, Wisconsin; Sidney, Montana|
|4a||-30 to -25 F||-31.7 to -34.4 C||Minneapolis/St.Paul, Minnesota; Lewistown, Montana|
|4b||-25 to -20 F||-28.9 to -31.6 C||Northwood, Iowa; Nebraska|
|5a||-20 to -15 F||-26.2 to -28.8 C||Des Moines, Iowa; Illinois|
|5b||-15 to -10 F||-23.4 to -26.1 C||Columbia, Missouri; Mansfield, Pennsylvania|
|6a||-10 to -5 F||-20.6 to -23.3 C||St. Louis, Missouri; Lebanon, Pennsylvania|
|6b||-5 to 0 F||-17.8 to -20.5 C||McMinnville, Tennessee; Branson, Missouri|
|7a||0 to 5 F||-15.0 to -17.7 C||Oklahoma City, Oklahoma; South Boston, Virginia|
|7b||5 to 10 F||-12.3 to -14.9 C||Little Rock, Arkansas; Griffin, Georgia|
|8a||10 to 15 F||-9.5 to -12.2 C||Tifton, Georgia; Dallas, Texas|
|8b||15 to 20 F||-6.7 to -9.4 C||Austin, Texas; Gainesville, Florida|
|9a||20 to 25 F||-3.9 to -6.6 C||Houston, Texas; St. Augustine, Florida|
|9b||25 to 30 F||-1.2 to -3.8 C||Brownsville, Texas; Fort Pierce, Florida|
|10a||30 to 35 F||1.6 to -1.1 C||Naples, Florida; Victorville, California|
|10b||35 to 40 F||4.4 to 1.7 C||Miami, Florida; Coral Gables, Florida|
|11||above 40 F||above 4.5 C||Honolulu, Hawaii; Mazatlan, Mexico|
USDA Miscellaneous Publication No. 1475. Issued January 1990.
Authored by Henry M. Cathey while Director, U.S. National Arboretum
Edited, formatted and prepared for the US National Arboretum web site by Ramon Jordan, March 1998 & Revised March 2001
U.S. National Arboretum, Agricultural Research Service, U.S. Department of Agriculture, Washington, DC 20002
Note: This publication is not copyrighted, and permission to reproduce all or any part of it is not required.
Even though you can provide more moisture to your garden than what falls naturally, it is helpful to know if you live in an area that, comparatively, gets lots of rain or just a little. For instance, if a plant is described as needing constant moisture, you probably don’t want to grow it in southern California.
One of the best ways to make your garden easier to care for and to increase your chances of success is to develop a garden design that combines trees, shrubs and perennials with similar growing preferences.
Daylilies, Sedums, Coneflowers, Baptisia and can be grouped together in hot, dry sunny locations. Areas with consistently moist soil will support Hakonechloa, Aruncus, and ferns, Shady areas that are irrigated are perfect for garden designs that include Hosta, Brunnera, Heuchera, ferns, Hellebores, Fothergilla and Hydrangea.
Another reliable guide for selecting plants that grow well in your area is to choose plants that are native to your region. In most cases they don’t need supplemental water or coddling if they are sited correctly. As an added bonus, they benefit wildlife in the form of food, cover or nesting sites. Some native perennials such as tall garden phlox (Phlox paniculata) offer nectar for butterflies and hummingbirds. Coneflowers (Echinacea) produce nectar for pollinators and have the added benefit of producing seed for songbirds.
One of the easiest ways to use natives is to simply incorporate them with your existing plantings or garden designs. You can spot them in here and there in your gardens or use them in large masses. Beds, borders, foundations plantings, woodlands and shrub rows are all potential planting areas.