A revised U.S. plant hardiness map has been put out by the National Arbor Day Foundation, based on numbers from 5,000 cooperative climate observation stations throughout the United States. The foundation forged ahead with their own revisions since the official USDA map update has stalled. One unofficial draft [PDF] does exist. A USDA spokesperson said their map delay is because of fine-tuning where to draw the zone lines; the agency also plans to incorporate other data such as wind.
posted on Jan 6, 2007 - View this thread