John Pacyga heads the landscape architecture firm Verdant Design. We’re in his backyard, surveying some beds he’s preparing for some native Kentucky plants. While many of his peers in the landscaping business are still putting in some of the more traditional exotic and ornamental plants, Pacyga is urging clients to consider designs that may hold up better as climate patterns fluctuate.
“In my plant selection then, what I’m looking at is plants that can basically be more survivable for our area,” says Pacyga.
Pacyga says plants aren’t simply going to have to adapt to higher temperatures and longer summers.
“What we’re seeing is not just a warming or cooling trend but, because of where we are in the United States, I think we’re going to have a little bit of both. I think we’re going to have a lot more cold and a lot more heat and drought, as well as potentially more storms,” Pacyga says.
Scientists aren’t always so keen on predicting how climate change will affect a region as small as, say, the Ohio River Valley. But landscapers and gardeners can tell you that changing conditions are affecting what they plant when and where. Many use the USDA’s plant hardiness zone map. It was last updated in 1990, although a revision is underway. More recently though, the American Horticultural Society and the National Arbor Day Foundation came out with their own versions. They used more recent climate data. And they found that some areas—including Kentucky—have shifted up a full zone. That means they’re five degrees warmer on average.
Whit Forrester graduated from college recently and is getting his own landscaping business up and running. He named it “Hotter Times” to draw attention to that trend.
“So I guess in the term of 10 to 20 years if things keep on escalating as they are, the droughts that we’ve seen for the past couple years could end up being way more severe, longer lasting. So, in terms of stuff that grows well here, it’s really tough to say, but it’s definitely going to be things that do better with less water,” says Forrester.
Forrester says he’s thinking beyond simply what kinds of plants and designs he wants to recommend to clients. He says that a changing climate is an opportunity to reexamine our relationship to the land… to ask whether or not we really need individual backyards with green grass lawns we have to water and mow. For instance, he says he’d love to see fewer fences in neighborhoods, less broken up parcels of land. He’d love to see more ofa community approach to landscaping.
“What that would mean for designing a landscape is that you would have healthier soil, you’d have more productive plants, you’d probably have better water-saving schemes, and also being able to have less fragmented habitats and ecosystems is also better for wildlife as well,” Forrester says.
Forrester says part of the reason for this healthier soil is that plants do best when they establish strong relationships with what he calls “fungal communities.” And those do well when they can spread out. Forrester says he hasn’t yet had the chance to test this theory. But researchers at Bernheim Arboretum are putting some gardening theories to the test. It’s a busy Saturday afternoon here, with families browsing native plants for sale. Executive director Mark Wourms shows off a cluster of experimental plant beds.
“What we’re testing here at Bernheim are four different groups of plants that all come from hot, dry environments,” says Wourms.
But the plants growing in these beds aren’t for your typical backyard. They’re for your roof—or green roof. Wourms is trying to figure out which plants will do best on rooftops in the region, especially as the climate changes.
“Our hypothesis is that Kentucky has a lot of native plants that will work very well in the Midwest. And one of the reasons we’re interest in that, from glades for example, might be rare and endangered,” Wourms says.
Some of those native plants include Kentucky’s very own kind of prickly pear cactus. Researchers will monitor how well each plant does in a variety of soils and then recommend the best combinations for future gardeners.