Zone 3 plants can withstand cold temperatures of -40 to -30°F. The upper Midwest states hold most of Zone 3, such as northern parts of Montana, North Dakota, Minnesota, Wisconsin, and Maine.

Hardiness Zone 4 comprises some of the coldest and northernmost areas of the continental United States. It stretches in a crescent shape from northern Idaho to northern New York and New England, and from the Canadian border south into parts of the Colorado Rockies.

Zone 5 starts in the Northeastern United States (including parts of New England, like Maine and New Hampshire, and mid-Atlantic states like New York, Pennsylvania, and West Virginia). It extends across the northern part of the Central US (including Minnesota, Iowa, Nebraska, and Wisconsin).

Zone 6 starts in the Mid-Atlantic United States (including parts of New York, New Jersey, Pennsylvania, and West Virginia) and extends slightly down the Atlantic Coast to include North Carolina, Maryland, and the District of Columbia.

Zone 7 includes Long Island, coastal New Jersey, eastern Maryland, most of Virginia and North Carolina, western South Carolina, southern Tennessee, the northern halves of Georgia, Alabama and Mississippi and much of Arkansas.

Zone 8 is one of the warmest zones, containing much of the southern quarter of the United States, including much of North Carolina, South Carolina, Georgia, Alabama, Mississippi, Florida, Louisiana, Arkansas, Texas, Arizona, California, and coastal Oregon and Washington.

Zone 9 includes Florida, Georgia, South Carolina, Texas, Alabama, Louisiana, Mississippi, Utah, New Mexico, Arizona, Nevada, California, Oregon, Washington, and Hawaii.

Zone 10 sees some of the hottest temperatures in the U.S., prevalent in tropical places such as Southern California and Southern Florida. Plants in this zone can handle temperatures as low as 30 to 40°F.

Zone 11 is one of the warmest hardiness zones around. Average minimum temperatures drop only slightly to 40 to 50 degrees F during the 'winter' months. This tropical climate is found mostly in Hawaii, Puerto Rico and some parts of Florida.