New USDA Hardiness Zone map has home gardeners abuzz


As long as I can remember, my mom has had a backyard garden.

Oh, she has perfected the art: bee-attracting flowers, ever-sturdier tomato supports, corn that reaches to the heavens. You can almost hear the harps in the other story on this page playing. It’s that pleasant.

My dad likes to brag about any meal made solely from backyard-grown produce. And the squeals of delight he utters while downing the corn? It’s almost scandalous.  

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But it was never really “my” thing. That is, not until my kids — now fully grown — were old enough for the lessons a garden had in store for them.

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It took all of one summer for me to claim ownership of the hobby. When I told my parents we were planting our first garden, my dad informed me: “We can now die happy.”

The use of the word “hobby” is purposeful. Make no mistake. There may be a harvest in the future, but it requires an up-front investment. You don’t really want to see the spreadsheets. There’s a reason why one of my favorite books on the subject is called “The $64 Tomato.”

When I moved to the mid-Willamette Valley more than two years ago, it was just about harvest time. As I went house-hunting, it was encouraging to see all the home gardens in and around Corvallis and Albany, especially in the front yards.

I learned later that’s because in many cases — including my own, now — the sun really doesn’t make it to the backyard. Still, the sprawling pumpkins and cucumbers on the vine only added to the curb appeal to my eyes.

Recreational farming in Oregon has offered other lessons. The pastoral setting is one of my favorite things about the area, but that doesn’t mean I could just transplant (hee!) what I thought were best practices.


Editor Penny Rosenberg’s garden in the promising days of early June 2023.

Where I could occasionally over-winter tomatoes and most of my herbs in Southern California, now they don’t make it to Thanksgiving. I can get serranos and jalapeño chiles to grow, but so far, no luck on habaneros. And citrus? Fahgettaboudit.    

The days are delightfully longer here, though not as hot. And at night, especially in the winter, it’s cold.

But not as cold as it used to be.

Home gardeners use something called the U.S. Department of Agriculture’s “Plant Hardiness Map,” which slices up the country into 13 color-coded, numbered zones (and those are divided into half-zones) based on the coldest temperature a plant would have to endure in any given area, averaged over a number of years.

Thus the need to be “hardy.”

The lower the number, the colder the area, Alaska being in Zone 1 and parts of Hawaii being in Zone 13. This helps recreational gardeners like myself select the veggies based on how likely they are to thrive.

Unless I’m just being stubborn and nostalgic. Which happens.

The USDA, with some help from Oregon State University, recently updated its maps, the first such makeover in 11 years. Like the bees attracted to my mom’s mums, it’s got everyone abuzz.

That’s because of two major changes. First, with 30 years of data, the average temperatures have risen enough to bump a full 50% of the country into a new, warmer zone. And secondly, the interactive map is now granular enough where you can find your own home’s zone.

The zones are in as small as quarter-mile increments. So even if your house is in 8b (where the coldest temperatures in winter are recorded between 15 and 20 degrees), like most of the mid-Willamette Valley, there are still some variations.

Topography matters, so if you’re in a plain or in the foothills, you’re going to experience weather slightly differently — in some cases enough to knock you into a different zone.

You can see this demonstrated on the new maps in eastern Linn County. Cascadia is now in what’s called 8a, warmer than North Albany during the winter. But the colder colors, goldenrod-ish into shades of green, aren’t far away. 

In fact, Cascadia’s and Lyons’ are two ZIP codes where the average coldest temperature has warmed up enough to be in a new half-zone. Both have gone from 8b to 8a. Welcome to the A-team.

Interestingly, they’re not the locales that have seen the biggest change in actual temperatures. That’s Blodgett in Benton County, which is 3 degrees warmer now in winter. The prior number just wasn’t close enough to “jump the line.”

In fact, almost all areas — except for Tangent, which didn’t budge — got warmer. 

Now this isn’t Philip Wenz’s column, so I’ll let him opine on the climate crisis side of things. But you may want to know that overall, the country is 2.5 degrees warmer than 2012, and that information was gathered by 13,412 weather stations, 5,429 more than the 2012 maps used, incorporating more historical data than ever.

Will that make a difference to my home garden? Not yet, at least. And habaneros, I never knew ya. I’m doubling up on serranos in 2024.

Find the map here:

Happy New Year, happy planning and happy planting, my fellow gardeners!

Penny Rosenberg is regional editor of three Lee Enterprises news publications in the Pacific Northwest. She earned a Master of Legal Studies from UCLA School of Law. She can be reached at [email protected] and 541-812-6111.


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