Don’t Let Winter Kill Your Plants. Follow Your USDA Hardiness Zone

Unless you’ve got a heated greenhouse, you won’t be able to grow citrus in Michigan or jasmine in New York for the simple fact that the winters are too cold. While the range limits of some plants are hard to miss — think cactuses, palm trees and citrus — others are less intuitive. Do rhododendrons grow in Maine? (Most of it.) Will lilacs thrive in Florida? (Probably not.)

A handy tool for answering these questions quickly is the US Department of Agriculture plant hardiness zone map.

While that’s a mouthful, it’s a simple way to determine which plants will survive your local winters. Below we’ll tell you how to find your hardiness zone, what that actually means and how to put your new found knowledge to the test. If you’re looking for more gardening tips, learn about growing herbs at home, planting trees the right way and why hydrangeas actually change color.

What are hardiness zones?

Hardiness zones are geographical areas divided up by climate that can be used to determine where different plants will grow best.

The USDA 2012 Plant Hardiness Zone Map.

USDA

The USDA Plant Hardiness Zone Map divides the United States and Canada into 13 zones, based on the average annual minimum winter temperature.

Each zone is, on average, 10 degrees warmer or colder in the winter than the zone next to it, with Zone 1 being the coldest and Zone 13 the hottest.  This broadly corresponds with a North to South pattern, but that’s not always the case. Things like mountains, lakes, desert topography and urban heat island effects can result in different zones in the same latitude and within just miles of each other.

The hardiness of a plant is largely measured by how well it can withstand cold winter temperatures, so something that can survive the minimum temperature in Zone 5 would find Zone 4 to be too cold. Many plants, fruits and vegetables sold at your local nursery or home improvement store include a hardiness zone suggestion on the label that is based on this map. The 2012 USDA Plant Hardiness Zone Map is the most current version, developed by the USDA’s Agricultural Research Service and Oregon State University’s PRISM Climate Group.

There are similar maps available for the UK and Australia.

Why do hardiness zones matter?

You can adjust for a lot of factors in your garden, like shade, water drainage or soil quality. What you can’t control is the weather. If you want a plant, vegetable or tree to survive and grow year after year, it must be able to tolerate conditions in your area.

That’s where the Plant Hardiness Zone Map comes in. It helps expert and amateur gardeners know which plants have the highest chance of success in their climate so they can avoid planting something that would never survive the winter or a spring frost.

Now playing: Watch this: See the CNET Smart Garden in action

1:40

The map is also a good way to compare your climate with the ideal climate for a particular plant you’re interested in growing. It doesn’t necessarily mean you can’t grow that plant in your area.

It just means you should take extra care to address its sensitivities. For example, if a vegetable grows better in a warmer climate, you should cover it anytime your area has a frost warning. 

Inconsistencies and exceptions

The USDA map can be a good guideline, but it isn’t a set of strict rules to be followed. The National Gardening Association notes that while the map does a good job of addressing climates of the eastern half of North America, it has a few shortcomings, especially in the west, where climates are much more varied thanks to mountains and deserts.

For example, though Seattle and Tucson are both in Zone 8 for temperature, there’s a large difference between the coastal, rain-heavy climate of Seattle and drier, inland Tucson. 

Hardiness zones can vary between towns and even within the same city. Denver is in a different zone than the suburban areas immediately surrounding it. 

USDA

If you’d like to view the zone for your area, you can use the USDA’s interactive map to find the plant hardiness zone in your exact location, down to the ZIP code. Remember, hardiness zones can differ across town.

A heat island effect in downtown areas might warrant a warmer zone than a less-populated suburban area. Elevation change can affect average temperatures, too.  While you might not notice big differences in which plants can survive in two zones so similar, it’s still important to know where your garden falls on the map.

In my area (7b), vegetables like radishes, lettuce, peas and onions are all likely to thrive when cared for correctly. You should also consider the direction and amount of sunlight your garden receives during the day. Your garden’s orientation to the sun and its shade play a huge role in the life cycle of your plants. 

Armed with the knowledge of your home’s hardiness zone, you can confidently sow, grow and harvest the plants most suited for your part of the country this season.

Tags:

apple-music listed on couponmatrix.ukbrandalley listed on couponmatrix.ukgood-energy listed on couponmatrix.ukmonitrex listed on couponmatrix.uksizzling-pub-company listed on couponmatrix.ukwhirli listed on couponmatrix.uk
apple-music listed on couponmatrix.ukCalling all music lovers and playlist-o-philes - Apple Music is your harmonious haven where you can access any song by any artist, whenever you want, wherever you want. It’s never been easier to play DJ with your personal faves and discover new artists, and with an Apple Music voucher, you can do all this on the cheap. Apple Music is a streaming platform created by people who get you so get on board today.
brandalley listed on couponmatrix.ukBrandAlley are a discount fashion retailer offering money off flash sales from top designers and brands. Launching new sales every day, they are a non-stop designer sale website! Every sale lasts up to 4-5 days with users being notified by email of all the latest deals, allowing you to discover something new and stylish every day. So double-down on your discount with a BrandAlley discount code to truly whittle a piece of designer clothing down to a price that's right for you.
good-energy listed on couponmatrix.ukThe way we source our energy can be a great cause for concern, especially with our seeming reliance on gas and nuclear sources. With Good Energy, you know you’re changing for the better – as almost all their energy is sourced by renewable means. Find a monthly price to save on with a Good Energy promo code and you’ll quickly see the benefits of switching providers, for both the environment and your personal balance.
monitrex listed on couponmatrix.ukFrom breathable T-shirts to fast-drying jackets, Montirex men’s activewear is created to keep you comfortable during a workout. The range of Montirex joggers and jackets for men and kids is perfect for active lifestyles, and with our money-saving tips you can stock up your wardrobe for less! Check out the hand-picked best offers from the sale, plus Montirex discount codes and delivery promotions. With student discounts and flash sales, you’ll always find a way to save at Montirex.
sizzling-pub-company listed on couponmatrix.ukWhether you’re celebrating a special occasion, watching the footy with your mates or bonding over a family lunch, you can expect the warmest of welcomes, tasty grub and red-hot offers from Sizzling Pubs. Explore our Sizzling Pubs vouchers to knock money off already affordable prices - with plenty to offer all the family, you could treat the whole gang for less. With friendly service and a home-away-from-home atmosphere, Sizzling Pubs will make your good times go further.
whirli listed on couponmatrix.ukWhirli is the new, greener way to play. Through the toy subscription service, simply borrow, play and then swap for a new toy. As well as reducing plastic waste, it also stops toys accumulating in your attic - plus, it saves you money overall too! Add a Whirli discount code to the mix and you could save a fortune on premium toys. You can even opt to buy the toys for less than retail price. Saving money while living sustainably? Count us in.