What does the USDA Hardiness Zone Map have to do with Must Have Perennials?
Hardiness of plants describes the plant’s ability to survive adverse growing conditions, resistance to cold, and is generally measured by the lowest temperature a plant can withstand. The range measures how well a plant can overwinter in the cooler temperatures to how well it can flourish in the heat.
An important focus for Must Have Perennials selections has been garden hardiness, with additional focus on performance and other distinguishing characteristics such as plant size and form, color, foliage pattern, heat, and drought tolerance.
Plant viability is determined in trial gardens around the world. Here is a chart that rates the zones for each genus of Must Have Perennial varieties.
Recently, The U.S. Department of Agriculture (USDA) has released a new version of its Plant Hardiness Zone Map (PHZM), for the first time since 2012. Read the PRESS RELEASE on the new map, which includes some details on how the averages are determined.
USDA’s Plant Hardiness Zone Map is the standard by which gardeners and growers can determine which plants are most likely to thrive in their location.