How climate change is also changing what we plant in Wisconsin

MADISON, Wis. — The earth is getting warmer.

Despite this cool spring, any gardener or farmer will tell you they are planting things they couldn’t 30 years ago.  They keep track of what will grow where by referring to the plant hardiness zones.

The U.S. Department of Agriculture first published the maps in 1960. The zones are based on the average annual minimum temperatures for any given spot. As you might suspect, climate change is changing the face of those maps. Southern Wisconsin was a zone 4 in 1990, but we’ve warmed to a zone 5 since the last maps were published in 2012.

Michael Notaro is the Associate Director of the Nelson Institute for Climatic Research on the University of Wisconsin-Madison Campus.

“(The) last few decades they’ve already advanced about one zone and likely we’re predicted by the end of the century to shift an additional zone in Wisconsin, and that would allow for some species that are more in the central U.S. to potentially be grown in Wisconsin,” Notaro says.

Scientists at the UW Foundation Seed Stocks center in Arlington, Wisconsin agree.

“Our growing zones are moving north, and that provides farmers the opportunity to grow corn, soybeans, alfalfa, forage crops for her livestock and higher-value crops,” Mark Kendall of the foundation says.

For the home garden enthusiast, a warmer climate means more options of plants you can put into the ground.

“It changes the plant palette of perennials that are hardy and mostly perennials,” says Laurie Sund, a plant buyer for the Bruce Company in Middleton. “You can more confidently plant lavender now, which is one of our most popular perennials. All those varieties are zone five.”

But a warming climate also makes for more weather extremes, especially if we continue to heat up the planet at the current rate.

“By the end of the century, we’d get much more substantial warming, much more substantial increases in heavy precipitation events, much more intensified weather conditions,” Notaro said.

Plant coach Lisa Briggs at the Bruce Company agrees.

“It’ll be super dry and then there will be a deluge and there’ll be flooding. It’s just like a roller coaster. So I think that’s what climate, how climate change is affecting the gardening industry,” Briggs said.