USDA Hardiness Ratings
There are many factors that affect the hardiness of plants. Tolerance to cold, heat, wind, wetness, and drought; soil conditions; plant size and age; light intensity; and day length all affect plant hardiness. While a plant may thrive in one area, it may not be as successful in another.
We have provided USDA hardiness ratings to help you in your selection of varieties. These ratings are for plants in the ground; keep in mind that perennials in pots may not be as hardy. The USDA map below encompasses 13 zones divided into finer increments and includes zone boundaries. To view more detailed state maps and look up zone information based on zip code, visit planthardiness.ars.usda.gov.