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New plant hardiness zone map issued

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#1 Rail Paul

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Posted 14 February 2012 - 02:43 PM

The media here in South Florida are buzzing with the release of a new plant hardiness map. Based on 30 years of observations, the map identifies areas where plants, etc can be planted with some confidence of survival. Based on such a short period, the USDA emphasized it's not a tool in the global warming wars as the observation period is too limited.

The National Map, insert zip code

The new map moves Palm Beach county into the same zone as the Florida Keys, among the most tropical areas in the US. It doesn't eliminate the problem of people buying plants that aren't suitable for their particular location, though.

The latest map is based on average annual winter low temperatures between 1976 and 2005 at 8,000 weather stations. It also considered for the first time such factors as changes in elevation and proximity to large bodies of water.

The slight shift in temperature zones for Palm Beach County might not be significant for everyone .

For example, gardeners who have visions of growing ultra-tropicals, plants that can't tolerate temperatures below 40 degrees, are still in for a disappointment.

Allen Sistrunk, director of Mounts Botanical Garden in West Palm Beach, said it's difficult to generalize temperatures when it comes to Palm Beach County.

"I have never seen a locale with as many micro-climates as Palm Beach County, not just the temperatures, but the soil and water. Everything but the sunlight varies dramatically in a matter of a few miles."

David Bache, sales director at Boynton Botanicals, said he thinks the fact that zone 9b has been obliterated from the county is misleading.

"People who live in the western part of Palm Beach County know from historical experience that there can be a significant difference in temperature," Bache said.

Another problem is that the zones are based solely on the lowest temperatures of the year and don't consider high temperatures and humidity. A plant that might grow in zone 10 in California where it's dry won't make it in humid Florida's zone 10, Bache said.

Whatever the zone, some people float into "zone denial" by purchasing a plant that's not recommended for their area, Nelis said.

“It must be remembered that there is nothing more difficult to plan, more doubtful of success, nor more dangerous to manage than a new system. For the initiator has the enmity of all who would profit by the preservation of the old institution and merely lukewarm defenders in those who gain by the new ones. ”
Niccolò Machiavelli

#2 Maison Rustique

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Posted 15 February 2012 - 12:44 AM

I haven't been able to figure out what grows here since we moved. Maybe this will help. According to this, we're in Zone 6a. :blink:
Don't use a big word where a diminutive one will suffice.

#3 GG Mora

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Posted 15 February 2012 - 01:46 AM

This initiative was actually in play a few years ago, and while we were bumped from 4 to 5, we had one -20 night last winter..and so the forsythia only bloomed where it had been insulated by the deep snow cover. Around the state, forsythia bloomed on its lower 2 - 3 ft. and was foliage only above that.