“What’s that smell?”
It’s what I’ve been asking myself in recent weeks. Not in a bad way; it’s an entrancing scent that’s been wafting through the air, at the Garden and in gardens I walk by in my neighborhood—but one I couldn’t quite place. I’ve been walking around, nose in the air, happy but perplexed.
Every spring we marvel at the sweet smells in the air. But perfumed breezes in autumn? And what an unusual perfume. Cilantro? With a hint of honey? What could it be?
“You’re smelling something that’s reminiscent of coriander, maybe cilantro?” said Jacob Burns, the Garden’s curator of herbaceous perennial plants. “You’re probably smelling Sporobolus heterolepis. Prairie dropseed.”
Welcome to a signature scent of late summer and early fall: the scent of prairie dropseed, a native grass.
Never mind the sweet scents of spring; this season’s plant aroma is in a class of its own. And it’s almost indescribable. I thought of cilantro partly because of the scent, but also because I couldn’t quite place it or compare it to anything else—like cilantro.
“Some people think it smells like buttered popcorn,” said Garden horticulturist Liz Rex, who cares for the Native Plant Garden.
The scent comes from the flowers, feathery panicles that bloom in late summer. I’ve smelled it walking by gardens where people have planted a few native prairie species.
Rex has been surrounded by it in places where it is planted en masse.
“The first year I was in the Native Plant Garden, it was almost overwhelming,” she said. “But now I really enjoy it and look forward to it.”
You can smell it in various spots in the Garden, Rex said—the Native Plant Garden, the restored prairie, the Kleinman Family Cove near the new Regenstein Learning Campus, the Regenstein Fruit & Vegetable Garden; and the rainwater glen outside the Daniel F. and Ada L. Rice Plant Conservation Science Center.
You can smell it in remnant prairies, said Joan O’Shaughnessy, prairie and river ecologist at the Garden—and if you do, that means the prairie is of high quality.
But you can also smell it in ordinary gardens. Native species are increasingly popular in front and back yards, and prairie dropseed (it gets its common name because of the way its mature seeds drop to the ground in autumn) is a Chicago-area superstar.
“It’s a wonderful garden plant because its growth form is low, which people like; it has this fountain-like look to the vegetation; and you can keep it over winter for appeal,” O’Shaughnessy said.
It can grow in both wettish and dry soil. Like many native plants of this region, it can tolerate drought. It can grow in that bane of the Chicago gardener’s existence, heavy clay soil. “It’s just a great plant,” she said.
It isn’t the only source of fall fragrance in the Garden. There is also the katsura tree (Cercidiphyllum japonicum).
“The leaves turn a really pretty fall yellow, and once they drop, they release a sugary aroma that smells like cotton candy,” Burns said. “Some liken it to caramel or even brown sugar.”
You can find a katsura on Evening Island by the trellis bridge, he said, and also in the Krasberg Rose Garden.
So while fall’s colors are rightfully beloved, it turns out that the season appeals to another sense, too. Go ahead and enjoy looking at the annual show of autumn colors—but don’t forget the autumn scents.
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