RENEGADE GARDENER

The lone voice of horticultural reason

“The new USDA Hardiness Zone map reflects the new normal for planting zones.”

Sorry, no. And if you don’t believe me, this spring check out the previously non- or barely hardy perennials, small trees and shrubs you planted in the past couple of years that you thought would survive just because a few years ago, some guys in Washington moved the lines on a map.

I never bought into it the redesign of the USDA Hardiness Zone map, perhaps because I’m from Minnesota. I saw warm winters in the 1960s, absurdly cold winters in the 1970s, and didn’t think for one minute that the miniscule rise in global temperature average – less than one degree, it turns out – that leveled off 15 years ago meant anything other than the normal fluctuation of planet temperatures.

In the early 1980s, Earth moved out of a well-documented mini-ice age, similar to the situation that occurred with the Medieval warming period that lasted 150 years. Each time, average temperature on the planet has nudged up. Accepting the premise that Earth has ever had a constant, never-changing temperature doesn’t make historical sense. It goes up, it goes down.

I wish they had left the USDA Zone map alone. The old one was performing quite nicely. This past year, it was far more accurate than the new one.

Don Engebretson
The Renegade Gardener