Plants of the Chicago Region

Featured plant: Sweet Flag

One of the projects underway at the Thomas Street Garden is a miniature rain garden. It's been a cool entryway into different ways of thinking about the garden. When the city is subject to serious cloudbursts, the rain garden will flood, and the water may stand there a few days before draining. Plants that are chosen for this area have to occupy a certain niche. Mostly what we are looking for are plants that live at the edges of wetlands and bogs, plants which are okay standing in a few inches of water but which don't need to be underwater all of the time. These plants are happy soaking up our extra rain, which might otherwise end up somewhere we don't want it.

I'm also trying to establish something like a naturalized landscape in the garden, someplace that will be attractive to the birds and bees in the region because it's representative of the surrounding region, and something which doesn't require a lot of care because that's the thing about naturalized landscapes -- they're already naturalized. Plants which are good at taking care of themselves are a lot easier to take care of, which means that they're great plants for community gardens.

While browsing the stacks at Sulzer Regional lately I came across Floyd Swink's 1969 volume Plants of the Chicago Region, published by the Morton Arboretum. Swink and his team exhaustively combed 22 counties surrounding the Chicago area, extending up into Wisconsin and even into Michigan. He lists every plant found growing wild in the area and notes its typical habitat, usual associates, and whether it is native or introduced. Within the first few pages he lists Acorus Calamus, Sweet Flag, a wetland grass with fragrant flowers and variegated iris-like leaves. Swink notes that it is not invasive, but that it "is usually found in old, stable marshes."

When I came across the entry for Acorus calamus I all at once realized that Sweet Flag was going to be the mascot for the rain garden, and that Swink's volume was going to be invaluable to me in figuring out how to establish a care free yet stable, mostly native but not exclusively so, super bio-diverse miniature landscape which was representative of Chicago itself. Aw yeah Urbs in Horto! A stable marsh is what the rain garden should represent. I've already added some Sweet Flag to the rain garden, and a few of its known associates - Orange Jewelweed, Marsh Fern, and Blue Flag Iris - are now on my list of plants to look out for.

Acorus gramineus is the shorter cousin to Acorus calamus. It reaches only a foot or so tall and makes an interesting choice for container arrangements. This shorter variety is the one I planted in the garden.

This is the state of the rock garden in August of 2012. The rain garden exists in the swale between the flagstone path and the rock garden. The area is still filling in with plantings. Columbine has done very well, and I'm trying out chocolate mint in the swale. Some perennials have been divided and cleared away in the rock garden and new seeds have been sown. Sweet Flag can be spotted in a few locations along the right hand side of the photo, toward the west end of the swale.