What does 'hardiness zone' refer to?

A 'hardiness zone' refers to a climatological zone for plant survival, which indicates the suitability of specific plants in various geographical areas based on climate conditions. This system helps gardeners and horticulturists determine which plants can thrive in their local environment based on factors such as temperature, frost dates, and overall climate conditions.

For instance, hardiness zones are often classified by average annual minimum temperatures, allowing one to identify which plants are likely to survive in a particular zone. This is crucial for successful gardening and landscaping, as planting species that are not suited to the local hardiness zone could lead to poor growth or plant failure.

In contrast, measures of soil moisture content pertain to different environmental factors that are not directly related to climatic conditions. Classifying flower types does not involve hardiness zones, as it focuses on botanical characteristics rather than survival based on climate. Similarly, plant height is a physical characteristic that has no direct correlation with the climatic conditions of a region.