Plant Guide: Knowing Your Cold Hardiness Zone

When picking plants and flowers to include in your garden there are always a few things you want to take into consideration. The first thing your mind inevitably turns to is aesthetics. How will this plant/flower look? How will it fit into your landscape? After that, you may consider things like, what type of soil you’ll need and how much water you have access to.

One important aspect to consider is your cold hardiness zone. Don’t know what I’m talking about? Don’t worry. The cold hardiness zones were created by the USDA and are a general guide to let you know what type of plants will survive in what zones based on the potential cold weather.

While determining the cold hardiness of a plant is not an exact science, the USDA takes many things into consideration when determining the number of a specific zone. The most important consideration is the average minimum temperature of the particular zone. However, the USDA also takes the different micro-climates into consideration before assigning a number.

According to the USDA cold hardiness map, zone 1 is the coldest area, with an average minimum temperature of -50 degrees Fahrenheit. The warmest zone is zone 11, which has an average minimum temperature of above 40 degrees Fahrenheit. Each zone has a 10-degree variance, and is further divided into two sub zones (A and B) that have a 5-degree variance.

It’s important to know your cold temperature zone so you can pick plants that have a corresponding number. All plants have been rated according to their cold zone (i.e. the coldest zone in which they will thrive). Most plant experts say since the cold hardiness zoning is not 100% precise, you can typically go up or down one zone for your area. It’s also okay to pick flowers from the warmest zones (which tend to be of a more tropical nature) as seasonal plants, adding a splash of color in the warmest months of the year.

All it takes is a little bit of research, and you can be sure you’re picking the plants that’ll do best in your area. And make your area look the best.