Wisconsin Master Gardener Practice Exam

Hardiness zones describe the minimum winter temperature a plant can reliably survive. The United States is divided into zones based on average annual minimum temperatures, with each zone representing roughly a 10-degree Fahrenheit range. A plant labeled for a given zone is expected to survive winter conditions down to that zone’s minimum; in locations with colder winters, it may survive only if kept within or above its tolerance, while milder winters are usually fine. This system helps gardeners choose plants that are suited to their local climate and avoid plants that won’t tolerate the cold. Other terms like growing zones, climate zones, or frost zones don’t pin down winter survival in the same precise, widely used way as hardiness zones.