Author Topic: New USDA Plant Hardiness Zone Update?  (Read 1778 times)

hammer524

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New USDA Plant Hardiness Zone Update?
« on: November 15, 2023, 12:23:30 AM »
According to the USDA Map, Phoenix is now 10a. I havent experienced a freeze in the city for a few years if my memory servers correct (Thank you Heat Island effect). Thanks to climate change, my dream of inground Durians may come true! /s

https://planthardiness.ars.usda.gov/

drymifolia

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Re: New USDA Plant Hardiness Zone Update?
« Reply #1 on: November 15, 2023, 03:21:37 AM »
And Seattle moved from 8b to 9a, as expected. I didn't expect to see pockets of 9b on the Olympic Peninsula. I know where the next experimental avocado orchard should go...

elouicious

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Re: New USDA Plant Hardiness Zone Update?
« Reply #2 on: November 15, 2023, 08:38:28 AM »
Houston moves to 9b despite two 8b storms

Jaboticaba45

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Re: New USDA Plant Hardiness Zone Update?
« Reply #3 on: November 15, 2023, 09:06:42 AM »
We moved up to 8a now...
Of course the number doesnt really matter cause once every few years we will get super duper cold.
But it does seem more accurate given it only went one or two degrees below 10f the last 10 years.

Tropheus76

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Re: New USDA Plant Hardiness Zone Update?
« Reply #4 on: November 15, 2023, 09:18:17 AM »
In Central FL I went from 9b to 10a. Guess I will toss all my heat lamps and tree blankets since I dont need to protect my mangos anymore and will start collecting ultra-tropicals to put in the ground. Woo-hoo! Will Durian grow in 10a? :P Maybe my Royal Poinciana wont freeze back to the roots every year now.
« Last Edit: November 15, 2023, 09:19:50 AM by Tropheus76 »

hipasfolk

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Re: New USDA Plant Hardiness Zone Update?
« Reply #5 on: November 15, 2023, 10:22:25 AM »
Was excited for a second that my small mangos might not be as high maintenance in winter but looks like my area is the only 9b in central FL that went unchanged, go figure.

Daintree

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Re: New USDA Plant Hardiness Zone Update?
« Reply #6 on: November 15, 2023, 10:30:33 AM »
Boise has been 7a since 2020, after being 6b for a long time.
However, the advice we give as Master Gardeners is to plant annuals as if we are zone 7, but plant perennials as if we are zone 6.
Some maps ditch the a and b, which are 5 degrees apart, and then our nurseries start bringing things in that are high zone 7, like only good to 10 degrees. Then last winter we had a low of -3.
People lost a lot of small, delicate trees.
Luckily, my greenhouses are zones 11b and 12b!

Carolyn in Boise
Still 6b in spite of the new map...

drymifolia

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Re: New USDA Plant Hardiness Zone Update?
« Reply #7 on: November 15, 2023, 11:45:52 AM »
Houston moves to 9b despite two 8b storms

Since hardiness zones are based on a 30-year average, you could have many many years that are colder (or milder) than that range, as long as the average annual minimum still falls in the range for that zone.

NateTheGreat

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Re: New USDA Plant Hardiness Zone Update?
« Reply #8 on: November 15, 2023, 12:30:33 PM »
Houston moves to 9b despite two 8b storms
The new maps are average annual lows for 1991-2020. IIRC those storms were more recent.

Bush2Beach

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Re: New USDA Plant Hardiness Zone Update?
« Reply #9 on: November 15, 2023, 08:16:06 PM »
Thanks USDA!

In Central FL I went from 9b to 10a. Guess I will toss all my heat lamps and tree blankets since I dont need to protect my mangos anymore and will start collecting ultra-tropicals to put in the ground. Woo-hoo! Will Durian grow in 10a? :P Maybe my Royal Poinciana wont freeze back to the roots every year now.

SDPirate

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Re: New USDA Plant Hardiness Zone Update?
« Reply #10 on: November 15, 2023, 10:34:23 PM »
Looks like both of my spots are 10b now.  Here's hoping to 11a in 20 years.  ;)

Epicatt2

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Re: New USDA Plant Hardiness Zone Update?
« Reply #11 on: November 16, 2023, 03:38:43 AM »
Glad to see on this new zone map that where I am in Tampa is now 10a,
but I won't hold my breath about that fer sure 'til after this winter.

Now all we need here in west central Florida is some much-needed rain.
(We're jealous of the Miami area's recent rain glut!)

Paul M.
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johnb51

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Re: New USDA Plant Hardiness Zone Update?
« Reply #12 on: November 16, 2023, 10:04:17 AM »
11a in north Broward here near the coast.  That feels about right.
John

Calusa

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Re: New USDA Plant Hardiness Zone Update?
« Reply #13 on: November 16, 2023, 01:25:05 PM »
Looks like I'm now 10b but I certainly didn't notice any change.

JohnG

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Re: New USDA Plant Hardiness Zone Update?
« Reply #14 on: November 16, 2023, 03:01:00 PM »
Tallahassee went from 8b to 9a. I feel like this opens up a whole new world.

greenerpasteur

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Re: New USDA Plant Hardiness Zone Update?
« Reply #15 on: November 16, 2023, 03:09:51 PM »
I'm 10B now but too bad I don't know anyone in SoCal with fruiting star apple. Anyone near Los Angeles growing one?

joe_OC

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Re: New USDA Plant Hardiness Zone Update?
« Reply #16 on: November 16, 2023, 03:25:28 PM »
Now I'm a 10b.  I will grow as a 10a zone, knowing that there are extremes every 20 years or so that can bring me down to a 9b.

K-Rimes

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Re: New USDA Plant Hardiness Zone Update?
« Reply #17 on: November 16, 2023, 03:34:10 PM »
Mine says I'm 10b / 10a now, but I know it's not really true due to being at 2200'. I had the coldest year by far last year, with two snow visits of 4".

Just cause it says mango zone doesn't mean it will be reliably...

hammer524

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Re: New USDA Plant Hardiness Zone Update?
« Reply #18 on: November 16, 2023, 03:36:01 PM »
Mine says I'm 10b / 10a now, but I know it's not really true due to being at 2200'. I had the coldest year by far last year, with two snow visits of 4".

Just cause it says mango zone doesn't mean it will be reliably...


Lies! From here on out I shall call the Grand Canyon state Mango-Zona!!!!

Fygee

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Re: New USDA Plant Hardiness Zone Update?
« Reply #19 on: November 16, 2023, 03:42:24 PM »
West Las Vegas remains 9a, and east/NLV/Henderson is now 9b.

I still think we should get a specific growing zone known just as "Ha! Good luck with that!". There's so many more challenges growing here than in other places that zone designations just don't suffice.
« Last Edit: November 16, 2023, 03:45:42 PM by Fygee »
Continuing my journey to disprove those who say "You can't grow that in the desert" since 2013.

drymifolia

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Re: New USDA Plant Hardiness Zone Update?
« Reply #20 on: November 16, 2023, 04:13:45 PM »
West Las Vegas remains 9a, and east/NLV/Henderson is now 9b.

I still think we should get a specific growing zone known just as "Ha! Good luck with that!". There's so many more challenges growing here than in other places that zone designations just don't suffice.

Same for Seattle for opposite reasons! No heat units, low highs in winter, cool nights even in summer... We may be 9a now but there's no way I could succeed with half the things you can grow in 9a in Florida, for example.

Geezerfarmz

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Re: New USDA Plant Hardiness Zone Update?
« Reply #21 on: November 17, 2023, 05:57:31 AM »
Was excited for a second that my small mangos might not be as high maintenance in winter but looks like my area is the only 9b in central FL that went unchanged, go figure.

Same here. There canít be that big of a difference between Casselberry/Longwood (now 10a) and Lake Mary/Sanford (still 9B)

TnTrobbie

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Re: New USDA Plant Hardiness Zone Update?
« Reply #22 on: November 18, 2023, 03:56:54 AM »
My zipcode/ zone is still 9B. *shakes clenched fists angrily to the sky*. (Lake Placid, FL).
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yoski

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Re: New USDA Plant Hardiness Zone Update?
« Reply #23 on: November 24, 2023, 02:33:59 PM »
Here in Sebring we went from 9b to 10a. There are weather records from the Avon Park, Highlands county Florida station, dating back to 1892. Here are all the highs/lows of any day with a low of 24F or less since 1892.
1981-1-14    55   18
1982-1-12    48   19
1989-12-24   44   20
1962-12-13   49   20
1982-1-13    62   20
1894-12-29   41   21
1977-1-20    41   21
1985-1-22    42   21
1981-1-13    47   21
1985-1-23     50   21
1962-12-14   59   21
1934-12-13   65   21
1985-1-21           74   21
1905-1-26           44   22
1989-12-25   45   22
1989-12-26   52   22
1895-2-8       -99.9   23
1985-12-27   48   23
2010-1-12    54   23
1981-12-12   57   23
1958-2-4           60   23
1980-3-3           61   23
1986-1-28           61   23
1983-12-25   70   23
1981-12-20   47   24
2010-1-6           49   24
1997-1-19           52   24
2010-12-28   52   24
1906-12-25   53   24
2001-1-5      54   24
1977-1-21    55   24
1981-1-18    55   24
1981-12-11   59   24
2010-1-13           62   24
1957-12-13   64   24

35 days in total. Of those 18 (!!) were in the 1980s. We are looking at around 13 decades so 2-3 below 24F nights per decade would be normal.
For the stats geeks, if you take Winter as Dec. 10 to Mar. 5 (=85 days). That gives a Z-score of 9.725 and a probability so small that any calculator will call is 0 (zero), even so it is a very small positive number.
Teh 2x2 contingency table is:
10183   17
832       18
The 1980s were an absolute freak in terms of cold winters. Let's hope we don't ever see that again. Why? My guesses are that they drained a lot of wetlands, so the cold air could penetrate further south. Also the Mt. Saint Helens explosion in 1980 might have contributed. Not sure what else. Maybe some unusual sun activity?
Also notice 1894-12-29 and 1895-2-8. Those dates are the "Great freeze in Florida" that caused Flagler to build his railroad all the way to the Keys.
« Last Edit: November 24, 2023, 02:54:17 PM by yoski »

yoski

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Re: New USDA Plant Hardiness Zone Update?
« Reply #24 on: November 24, 2023, 02:43:48 PM »
My zipcode/ zone is still 9B. *shakes clenched fists angrily to the sky*. (Lake Placid, FL).
South or East of the lakes you're definitely in 10a. On US-27 you have 2 very large Mango trees with a single trunk, one where the pineapple is and another on the northbound side between lake McCoy and Highway Park. Both of them are at minimum 50 years old, probably 70-80. A single trunk means that they never froze back to the ground.