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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.