Let’s take a little trip back in time…
When I was a kid, I celebrated Thanksgiving with unusual aplomb. Part of it was recognizing the few days off from school as a prelude to a longer winter break, but the memories I hold most dear involve bundling up and taking a post-dinner hike into the woods.
An increasingly rare snowy Thanksgiving day. Photo by Matt Suwak.
Here I would skirt the tree lines separating farmers’ fields and stomp my way through the snow.
Eventually I’d find myself standing square in the center of a barren field, surrounded by yellow and gray grasses and bordered by leafless trees. Soon I’d hear that goofy and somehow soothing call of Canadian geese flying south towards warmer climates.
It was a favorite tradition, but it’s a rare happening to see snow on Thanksgiving nowadays. As a gardener, these climatic changes are vital to understanding the evolving state of our yards and our gardens.
Changes in the Garden
Those folks who’ve been gardening since the 2000s and before have probably noticed changes in growing patterns between then and now.
Annuals that ought to be toast by September are blooming through to November. Just a few weeks ago, I witnessed very confused apple trees and forsythia pushing out a late-autumn bloom.
Sometimes it’s a sight of joy and excitement, and other times it’s a disconcerting observation when you’re wondering why your peppers are pushing new flowers in the first week of November. If you’ve seen these changes firsthand, you’re not alone.
Larger harvests are a nice byproduct of warmer temperatures.
A Look at the USDA Growing Zone Map
The United States Department of Agriculture has been a reliable authority for determining what plants can grow where in the United States. It relies on decades of records of weather patterns to determine the average highs and lows of any specific area.
Plants like the desert rose (Adenium) will be more likely to bloom unassisted in certain areas.
The USDA Plant Hardiness Zone Map’s origins stretch back to the 1960s, when Henry Skinner of the United States National Arboretum first devised a working map of plant hardiness zones. His original vision has transmuted into the USDA zones we’re familiar with today.
Back in 1990, a growing database of climatic records prompted the first major change to this map, and in 2012 the map was updated again. We haven’t had an update since, and we probably shouldn’t expect one for some time.
But How Does It Work?
The plant hardiness zone map is separated into regions by average low temperature. The regions range from 1 to 13, with each individual region split into an “a” or “b” category.
You can view interactive USDA Growing Zone Maps and also in various formats.
Each digit between 1 and 13 represents a 10-degree difference in the average low temperature, while the “a” or “b” narrows this temperature gap down to 5-degree increments.
Unexpected snowfalls go hand in hand with fluctuating USDA climate zones.
For example, Zone 7 has an average low temperature of 0 to 10 degrees Fahrenheit; 7a has a low of 0 to 5 degrees, and 7b has a low of 5 to 10 degrees. Zone 6 has an average low between -10 and 0 degrees, and Zone 8 has an average low between 10 and 20 degrees Fahrenheit.
The Climes, They Are A-Changin’
Although our planet is definitely getting warmer, this change in the USDA plant hardiness measurements between 1990 and 2012 is officially attributed to more accurate temperature measurements, and a system that takes into account a location’s closeness to bodies of water, elevation, and other micro-climate effects.
It’s getting warm out there!
However, just because a 6b in 1990 was relabeled as a 7a in 2012, it doesn’t necessarily indicate that certain plants can now grow in these warmer locations. In some areas, these climactic changes have been more gradual. In others, you can’t help but notice them.
According to an article published in November 2019 in the Anchorage Daily News, these changes and their effects in the garden are undeniable. Gardening columnist Jeff Lowenfels says warming is happening two to three times faster in the Arctic than it is in other places on Earth, and at the time of writing he tracks a 20-month period of record-breaking temperatures. This affects planting times, bloom periods, and everything else, even the way gardeners may need to make adjustments to deal with weeds and newly invasive plants.
If you started your garden before 2012, subtle changes in climate could explain why harvest times and dates of first and last blooms have shifted. And if you’ve been paying close attention to the more sensitive plants in your garden in the heat of summer, or the hardier plants during the winter chill, things may have changed since then as well.
Sensitive to the cold, canna lilies may respond well to warmer climates.
As always, the gardener must take into account the natural habitat of any plant they wish to grow (read more about when full sun doesn’t really mean full sun, for a start). Some plants thrive in hot weather, but also demand a humid and moist environment.
So, the next time you’re shopping for plants and reading the tags like a dutiful gardener, keep in mind that the climes, they are a-changin’.
Longer summers and warmer weather can exacerbate weather patterns on a large scale, like the prolonged California drought in 2016 did.
To see what hardiness zone you live in, visit the USDA Plant Hardiness Zone Map website and pop in your zip code to find out. Keep in mind that the data you’re looking at was analyzed and documented in 2012, and consult your gardening journal as a point of comparison so you can adjust accordingly when planning and planting your first vegetable garden.
Hotter weather means extra watering.
What differences have you noted in your garden in the last few years, with the consistently warmer weather, frosts that arrive earlier, or periods of drought or excessive rain? Share in the comments!
Snowy road photo by Matt Suwak, © Ask the Experts, LLC. ALL RIGHTS RESERVED. See our TOS for more details. Uncredited photos: . Last updated November 22, 2019. With additional writing and editing by Allison Sidhu.
About Matt Suwak
Matt Suwak was reared by the bear and the bobcat and the coyote of rural Pennsylvania. This upbringing keeps him permanently affixed to the outdoors where most of his personal time is invested in gardening, bird watching, and hiking. He presently resides in Philadelphia and works under the sun as a landscaper and gardener, and by moonlight as a writer. An incessant questioning of “Why?” affords him countless opportunities to ponder the (in)significance of the great and the small. He considers folksy adages priceless treasures and is fueled almost entirely by beer and hot sauce.
New York Planting Zones – USDA Map Of New York Growing Zones
Gardening in New York – How to Use the New York USDA Plant Hardiness Map
The USDA began producing plant hardiness maps in 1960 and has been improving its accurateness ever since. In 2012, a new zone hardiness map was released that took the place of the previous 1990 map. The new map includes 13 zones. Above is the New York planting map that indicates the planting regions specific to the state of New York.
There is a 10-degree difference between each planting zone and a 5-degree difference between sub zones. Gardeners who wish to have a thriving garden should heed the zone data when considering what to plant. Most growers have adopted the plant hardiness information, and this zone information is generally included on the care instructions tag on flowers, shrubs and trees.
According to the USDA map, New York zones include a wide range from 3a to 7b. Those living in zone 3a will not necessarily be able to grow the same plants that can be grown in 7b. Elevation and proximity to large bodies of water play a role in the winter extreme low temperature variance seen on the map.
Although the new USDA plant hardiness map is more sophisticated than previous versions, it is still not a guarantee. Gardeners should be aware that there are other factors that influence plant hardiness including how and where the plant is placed in the landscape and how it is cared for. Use the data provided by the hardiness map as a foundation when choosing plants and be sure to do your research before incorporating any flower, shrub or tree into your landscape.
At Westchester Tree Life, our goal is for your plants, trees and shrubs to maintain a constant peak of health! To give your plants, shrubs and trees a healthy start, it is vital to select an area they would best thrive. If you’ve ever browsed online for seeds or bulbs, you’ve probably seen a reference to hardiness zones. Knowing all about hardiness zones is a great way to maximize the success of your plantings and to know which plants may be vulnerable during the harsher times of year. If you have any questions or concerns about your plant’s health, ask a Westchester Tree Life professional! Call Westchester Tree Life here: (914) 238-0069
Westchester Tree Life Explains Hardiness Zones:
So what does hardiness zone refer to? To put it simply, the United States is divided into hardiness zones based on each region’s weather patterns. There are 13 hardiness zones in the US. The lower the number, the colder the winter. For example, Louisiana is in Zone 9 while North Dakota is mainly in Zone 3. If you’re considering planting a shrub best suited to hardiness zone 5-7, you want to make sure your location falls within that range. Otherwise, your plants may not survive until spring.
It’s also important to know that some plants actually need a certain level of cold in order to survive. A plant that is hardy enough to grow in northern Maine may not grow in Florida. The hardiness zones in one state can vary widely. Here in New York, you could be in zone 3, 4, 5, 6, or 7! Our own local Westchester County area, as well as New York City, northern New Jersey, Rockland county, southern Connecticut, and parts of Long Island are in hardiness zone 6.
While hardiness zones can be a useful guide in knowing which plants can thrive in your yard, there are other factors to take into consideration. Wind, rainfall, humidity, soil composition, and sunlight can all effect the health and growth of your plants. When considering adding a new tree, shrub, or perennial to your existing greenery, it’s always a good idea to seek the advice of an expert.
U.S.A. Outdated already? The U.S.D.A.’s Plant Hardiness Zone Map for 2012.
For gardeners sad to see the summer drawing to a close, there’s some comfort to be drawn from the fall planting season for perennials, trees and shrubs, which is just around the corner. What’s more, there’s the novelty of this year’s updated Plant Hardiness Zone Map, released early this year.
The previous version of the map was issued in 2003, but the agency fielded so much criticism over the ways in which it incorporated climate change into the equation — too little and too much — that the map was withdrawn, and professional and amateur planters were left with guidelines dating back to 1990.
The 2012 version shows that planting zones have been shifting northward as winters become more mild. But a researcher contends that this long-awaited map is already outdated.
Nir Krakauer, an assistant professor of civil engineering at the Grove School of Engineering at City College of New York, has overhauled the U.S.D.A.’s hardiness map to better account for recent temperature changes. Unlike the U.S.D.A., which came up with its planting zones by using average annual minimum temperatures from 1975 to 2005, Mr. Krakauer looked at long-term temperature trends, including recent data that shows that winter temperatures are increasing more rapidly than summer temperatures. His results were published this week in Advances in Meteorology.
According to his calculations, about one-third of the country has already shifted half-zones by comparison with the map, and more than one-fifth has shifted a full zone. (Each zone has a minimum temperature range of 10 degrees Fahrenheit, and half zones have a 5-degree range.)
Dr. Krakauer has also created an online calculator where anyone can plug in a longitude and latitude and see the adjusted temperature change. In New York City, for example, his calculator shows that the minimum winter temperature is 1.5 degrees Celsius warmer (2.7 degrees Fahrenheit warmer) than suggested by the hardiness map.
“It’s difficult to give specific examples of plants you can grow somewhere that you couldn’t before, because plant varieties are also changing so much,” Mr. Krakauer said, “But generally speaking, you can now grow varieties 100 miles further north than you could about 30 years ago.”
“I’m a gardener, so my results interest me on a personal level, but I was also really struck by just how much temperatures have changed,” he said.
“We talk about dangerous climate change as being two degrees centigrade above pre-industrial values,” Dr. Krakauer explained. “Over all, we are only at about 0.8 degrees warmer today, but these results show that U.S. winter temperatures, at least, have already reached that ominous two-degree mark.”