Quite contrary

Monday, April 28, 2008 | 2:06 a.m.

Gardeners who wonder whether a tree will grow in Brooklyn or a tomato will grow in Phoenix may soon discover that the answer depends on whom they ask.

The Department of Agriculture creates the official multicolor climate zone map that U.S. growers depend on to decide how well a certain plant may survive in their area.

But the most recent map is from 1990 and doesn’t reflect recent global warming trends.

And a growing number of horticulturists — including those at the American Horticultural Society — say USDA officials are reluctant to release an update unless it minimizes such warming trends.

The society has adopted and posted on its Web site a 2003 update to the map that was created by Mark Kramer, a meteorologist who created the USDA’s official 1990 version.

Agency officials say they rejected Kramer’s update because he analyzed only 16 years of weather data, and they want 30 years.

It’s a curious position, considering the USDA used 13 years of data to create the 1990 map.

Kelly Redmond, of the Desert Research Institute in Reno, told USA Today that climate changes are happening faster than in the past. The U.N. Intergovernmental Panel on Climate Change has noted that 11 of the 12 warmest years since 1850 occurred from 1995 to 2006, which means gardeners, and those who create zone maps for them, need to be more flexible, Redmond says.

Nursery industry officials — who usually offer money-back guarantees on plants for the first year — worry that a map showing a general warming trend could encourage Northern gardeners to try new plants that may not survive a cold snap, such as the one that gripped the nation this year.

Kramer told USA Today that when nature changes “industry should change with it.” But that’s not a popular position for the Bush administration, which holds a dim view of global warming.

Perhaps the idea of a climate zone map that acknowledges global warming’s effects will bloom next spring, when a new crop of officials is in the White House.