What USDA Hardiness Zone Am I In? And Why Does That Matter?! Let’s Break It Down

If you love to garden, you’ve probably heard the term USDA Hardiness zone or seen it on plant tags. We include it every time we write about our favorite perennials, shrubs and trees here at PureWow to help you select the right plants for your region. But what does a hardiness zone really tell you— and more importantly, why the heck does it matter?

The first-ever idea of a hardiness zone map was created by Arnold Arboretum of Harvard University in 1927. The most recent version was created by the USDA in 2012 (find your hardiness zone here) and still is the current standard. While other organizations have devised their own versions, they’re not as widely used.

So what makes it the gold standard? And how do you figure out what zone you’re in? Read on for everything you need to know.

The USDA Hardiness Zone map is based on the average annual minimum temperature in a region, divided by 10-degree-Fahrenheit zones. The zones are numbered from two to 11, and they provide a way for gardeners to figure out which plants are most likely to thrive and survive winters in a specific location.

However, the map is by no means a guarantee that your plant will do well. Too many other factors affect your garden such as drought, humidity, disease, pests, microclimates in your yard (such as planting up against a south-facing wall, which may increase the temperature a few degrees in that part of the garden), and even whether something was planted correctly.

One thing the map also is not good at is evaluating a plant’s heat tolerance. That information is best gleaned by talking to a local nursery for guidance on how well certain plants do in the heat. It also does not indicate a plant’s watering needs.

Figuring out your hardiness zone is as simple as visiting the USDA website and taking a look at its Hardiness Zone map. There's an address search bar at the top that lets you type in your zip code, revealing exactly which number corresponds to your area. Look for that number when shopping for plants.

Not really, because most annuals are meant to be planted and enjoyed for only one growing season. That means you can grow just about any annual anywhere in the country. But there are some exceptions: Some plants may be treated as annuals in cold climates, such as rosemary or lantana, but would be considered perennials in warmer parts of the country.

Basically, knowing your hardiness zone and buying a plant that is suited for that zone is your best bet for gardening success. While there are never any guarantees your plant will thrive (hello, hailstorm that flattened your greenery!), it’s an essential first step to finding plants that are best suited for your region’s winters.

Another heads up: Some online nurseries will ask your zip code to advise your hardiness zone. But others will ship you a plant, even if it’s not suited for your zone. You’ll sometimes find plants outside your hardiness zone at big box retailers, too. That’s why it’s imperative to read the plant tag or description so you know exactly what you’re buying. It’s totally fine to experiment with a plant a zone or two outside of yours, but do so with your eyes wide open.

Arricca Elin SanSone is a gardener with more than 15 years of experience. In addition to PureWow, she writes for Prevention, Country Living, Veranda, The Spruce, and many other national publications.

She also trials new plant cultivars and field tests garden products to evaluate practicality and durability.

PureWow is the best friend you never had when it comes to finding the best, most useful lifestyle products online. Founded in 2010, our company’s editors and writers have spent more than a decade shopping online, digging through sales and putting our home goods, beauty finds, wellness picks and more through the wringer—all to help you determine which ones are actually worth your hard-earned cash. From our PureWow100 series, which sees each and every item we test being ranked on a 100-point scale of awesomeness, to the painstakingly curated lists our fashion, beauty, cooking, home and family editors create as vertical experts, you can trust that our recommendations include some of the greatest items you’ll find on the internet. Whether you're looking for travel-size hair dryers you can take on-the-go or women’s walking shoes that won’t hurt your feet, we’ve got you covered.