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Daniel Munoz, NorthJersey.com
Bruce Crawford has managed gardens for more than 20 years — 18 of them at Rutgers University, where he oversaw its 160-acre garden with more than 60 designed acres of beds, tree and shrub collection, lawns and paths.
The guy knows plants.
Some specimens seen more often in colder climates — like the Serbian spruce tree and snow-in-summer, those silvery-grey flowers seen in the alpine regions of Europe — that “often looked ‘unhappy’ during the summer are now not doing well at all in New Jersey,” said Crawford, who now oversees three botanic gardens in Morris County.
It’s just too hot for them.
According to gardening experts, New Jersey is getting warmer, and for those with a green thumb, that carries the headache of new plants and new bugs that threaten them. Gardeners, nurseries and farmers will have to adjust as time goes on.
In 2023, the U.S. Department of Agriculture put out its first update since 2012 to the “Plant Hardiness Zone Map,” which the agency estimates is used by 80 million Americans, primarily gardeners and growers.
The map is based on 30-year averages of the lowest annual temperature in certain locations, and divided into zones and half-zones by 10- and 5-degrees Fahrenheit, according to the USDA.
Most of New Jersey shifted into a warmer zone, meaning that, to some extent, plants that do well in warmer weather could grow in the state.
In New Jersey, the zones range from 6b to 8a. Here are the zones for a handful of towns across Northern New Jersey:
- Mahwah: Zone 7a in 2023, Zone 6b in 2012. 2 degree Fahrenheit temperature increase during those 11 years
- Montclair: Zone 7a in 2012 and 2023. 2 degree Fahrenheit increase during those 11 years
- Newton: Zone 6b in 2023. Zone 6a in 2012. 5 degree Fahrenheit increase during those 11 years
- Paramus, Zone 7a in 2012 and 2023. 3 degree Fahrenheit increase during those 11 years
- Pequannock: Zone 7a in 2023, Zone 6b in 2012. 3 degree Fahrenheit increase during those 11 years
- Wayne: Zone 7a in 2023. Zone 6b in 2012. 3 degree Fahrenheit increase during those 11 years
The shifts mean new plants can be grown in New Jersey, but gardeners also have to stress about new bugs that could eat their plants, like aphids and certain types of beetles, according to the Sow True Seed blog based in North Carolina.
“While not a major change, this does indicate that some species that grow better in warmer climates may fare better in New Jersey,” reads an email from Tom Knezick, president of Pinelands Nursery & Supply in Burlington County, and a board member of the New Jersey Nursery and Landscape Association
“This may make some gardeners more comfortable trying out some more tropical type plants, or tempt native plant enthusiasts to introduce more southern friendly species to their yards to keep up with climate change.”
That’s not to say New Jersey is a warm climate suited for tropical plants, according to experts.
“We still experience four seasons here. We still experience cold,” said Tyler Cerbo, who runs Cerbo’s Parsippany Greenhouse in Morris County.
How has warmer weather changed NJ’s gardening industry?
Tyler Cerbo, of Cerbo’s Parsipanny Greenhouse, poses for photo, Thursday, Apr. 24, 2025. Anne-Marie Caruso/ NorthJersey.com
Almost everything Cerbo’s sells is growable in New Jersey, Tyler said.
“We don’t carry or sell anything dramatically different than we did 20 years ago,” he said in a phone interview.
And the industry is very much at the mercy of the weather, he said. So a rainy weekend in late April, during prime growing season, could take a bite out of the business’s revenue.
The state’s zone changes have been on the mind of Jessie Babbitt, who runs Bare Flower Farm in Somerset County. The farm has experimented with growing plants that fare better in warmer, more humid weather.
“More flower farmers are able to overwinter things like dahlias, which previously would not have made it in our winters,” she said in an email.
In the future, garden centers will likely choose plant variants more resistant to heat as well as pests that do well in warmer climates, said Brittney Portes, an urban gardening consultant and manager of the community garden at Montclair State University.
“To the average consumer, it might look the same because it’s a tomato plant,” Portes said in an email.
“But what they might not understand is that the same beloved tomato variety they grow each year might not do well in our climate over time because it is not heat-resistant, and they will have to grow a new tomato variety that is.”
Is it climate change?
In recent years, New Jersey has been buffeted by “warmer winters and hotter, longer summer droughts,” reads an April 2024 post by Jay Watson, co-executive director of the New Jersey Conservation Foundation, a Somerset County nonprofit that handles land preservation.
All told, half the country shifted to a warmer zone in the 11 years between the two maps while the other half hasn’t, according to a December 2023 post by University of Washington’s College of the Environment in Seattle.
Watson wrote that certain plants native to New Jersey — like the sugar maples and New Jersey’s state tree, the northern red oak — may struggle to adapt to warmer temperatures.
But “data shows that despite rising average temperatures, New Jersey still experiences significant periods of intense cold,” said Ramu Govindasamy, a professor at the Rutgers Department of Agricultural, Food and Resource Economics.
“Several of the recent winters have recorded temperatures well below zero, demonstrating that extreme cold spells have not disappeared,” he said.
Plants that fare well in warmer weather but not the cold may not necessarily do well in New Jersey given its cold winters.
“Climate change does not simply make every season uniformly warmer. Instead, it introduces greater variability, forcing farmers, conservationists, and policymakers to prepare for a wider range of possible conditions,” Govindasamy said.
Daniel Munoz covers business, consumer affairs, labor and the economy for NorthJersey.com and The Record.