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Draft 2003 USDA Hardiness Map - new Tropical Zones

Posted by jenny_in_SE_PA USDA7 Sunset 32 (My Page) on
Sun, Jul 13, 03 at 9:21

To all of you current Hawaiian residents:

Do check out the draft of the updated 2003 USDA Hardiness Zone map that is currently posted on the AHS (American Horticultural Society) website here. It is based on data from 1987 - 2001. Once it has been peer-reviewed and approved, this map will replace the current USDA Hardiness map which was last updated in 1990 and that used data from 1974 - 1986. The actual map can be downloaded from a separate link on that site. The map is large and will take some time to download, particularly on a dialup (aout 5 minutes on broadband and up to 30 minutes on dialup). The map is viewable via Adobe Acrobat and there is a "Zoom" feature from Acrobat so that you can point it to your state and zoom in to county level to see the new Zone divisions.

One of the major changes that directly impacts Hawai'i is that 3 additional Hardiness Zones (for a total of 4 "Tropical" Zones) have been created - Zones 12 - 14, so that the island chain is no longer lumped into a generic "Zone 11" (frost free). I am sure that you all know that there are many variations in climate within and among the various islands depending on elevation and position relative to the tradewinds and along the coasts, and that impacts your winter temperatures.

The new Tropical Zone divisions now describe avg. winter min. temps in the same type of 10 degree ranges that the lower Zones use and will be the following: 40 F - 50 F (Zone 11), 50 F - 60 F (Zone 12), 60 F - 70 F (Zone 13), 70 F+ (Zone 14). From my following certain threads on the Tropicals Forum, I understand that there are a number of temperature sensitive tropicals that can suffer with temps below 60 F, yet the old USDA Hardiness maps didn't subdivide to account for this. Thus hopefully this will help in your selection of shrubs and perenials and how successful they can be in your climates (of course knowing there are always microclimates and other factors that will impact plant health).

I would be interested to hear how you all feel about this! :-)

Follow-Up Postings:

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

Very interesting as I'll be moving there to Pearl Harbor next year and wondered what the growing season was like out there.

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

  • Posted by SoCal23 USDA10/Sunset23 (My Page) on
    Mon, Jul 14, 03 at 9:22

LOL, you'll have to redefine your terms, there is no season when things aren't growing there.

Here is a link that might be useful: Averages and Records for Pearl Harbor, HI

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

Oh how I love Hawaii!
just reading the avg. highs and lows from that Pearl Harbor chart makes me so happy. I cant wait to go back. I was in Kauai in may. I cant wai to see all the other islands and also visit beautiful Kauai again. someday I hope to be lucky enough to stay for a longer time or possibly live and garden there. thanks spike, i will visit this forum every time I come to GW and dream of Hawaii

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

Pinky21, I lived and gardened on Kauai. Take my advice: RENT first. The island is extremely beautiful and the climate can't be beat. But living there is not as easy as you might think.

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

WOW, Pearl Harbor has less rain than Los Angeles!
I guess those scenes from Hawaii 5-0 were filmed there after all. I see that it's very dry and it looks exactly like the foothills around SoCal. I hope the USDA make the zone 11 in SoCal bigger, the way it really is, and more obvious on there map.

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

Aloha Jenny

Re-zoning Hawaii is an excellent idea. I live on the big Island at the 1700 ft elevation and will be in zone 12.


RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

Hello to all, I live in Hilo and according to the temperature range I fall at the top end of Zone 12/bottom of zone 13. Now if nurserys will correct their zone notations, it will help. My biggest concern is will I have enough of a chill for some plants!

RE: Draft 2003 USDA Hardiness Map - new Tropical Zones

  • Posted by ARAD 10USDA/25SUNSET (My Page) on
    Sat, May 1, 04 at 17:29

lapalms, the total precipitation for Pearl Harbour is 152.14 inches/year. Do you REALLY think LA gets more than that??? LOL. Yeah, in a decade...As for zone 11 in California...forget about it.

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