Prairie Blooms Beckon

It’s time for a visit to the Dixon Prairie to savor late spring flowers and the pollinators visiting these plants.

White wild indigo (Baptisia alba var. macrophylla)
White wild indigo (Baptisia alba var. macrophylla)

A standout plant, looking almost like a small shrub, is white wild indigo (Baptisia alba). This is the white-flowered cousin to blue wild indigo (Baptisia australis); this plant, not native to the Chicago region, was historically a source for blue dye. Both species are in the pea family. Many prairie plants belong to the pea family; other important families of the prairie are sunflower, sedge, and grass. Queen and worker bumblebees primarily pollinate white wild indigo. Their large size allows them to push down the lower part of the flower (the keel) and thus expose the pollen producing anthers.

A rich palette of blue flowering plants from the Ohio spiderwort (Tradescantia ohiensis) surrounds the white wild indigo plants. A variety of bees and butterflies might be seen visiting these plants, bumblebees being the primary pollinator. Butterflies, in their quest for nectar, will not be rewarded for their visit, however, since Ohio spiderwort doesn’t have nectar.

Spiderwort (Tradescantia 'Sweet Kate') and coneflowers bloom on the Prairie.
Spiderwort (Tradescantia ‘Sweet Kate’) and coneflowers bloom on the prairie.

The prairie also currently hosts numbers of white tubular flowers, foxglove beardtongue (Penstemon digitalis). On the lower half of the flower is a large hairy sterile stamen (the part of the flower that produces pollen); perhaps this feature is the origin of the plant’s common name. Pollinators, primarily bees, must work their way past this sterile stamen to reach pollen. This effort increases the likelihood of pollen being deposited on the stigma, the organ that is receptive to pollen. Those willing to observe these flowers for a while might be rewarded with witnessing some territory defending. The male of an introduced bee, the European wool carder bee, with sharp spines on their abdomens, will attack other males who come in the vicinity of the female when she is foraging for nectar.

Pale coneflower (Echinacea pallida)
Pale coneflower (Echinacea pallida)

Just opening on the gravel hill prairie is the pale coneflower (Echinacea pallida). The narrower leaves of this plant distinguish it from the commonly planted purple coneflower (Echinacea purpurea) (sometimes called broad-leaved coneflower). Like other members of the sunflower or aster family, the coneflower has what appears to be a singular flower but is actually a head of many flowers. This species has what are called ray and disc flowers. Some sunflower plants have only disc flowers while others, such as dandelions, only ray flowers. This plant is a preferred nectar plant of both bees and butterflies.

Moving into summer, this palette will change and reveal a new tapestry of grasses and wildflowers. To witness the full bounty of the prairie, a prairie visit should be a weekly affair.


©2016 Chicago Botanic Garden and my.chicagobotanic.org

Power-Line Prairie

You know it’s bad news when the troublemakers—such as Queen Anne’s lace, purple loosestrife, or another invasive species—start to take hold in the landscape. Imagine the sight at Illinois Beach State Park when a dense thicket of more than 20 invasive species took over a ten-acre utility corridor—and began to grow steadily toward 50-foot-high power lines.

To ComEd, which manages the utility corridor, the thicket was potentially hazardous. According to safety regulations, plants under such transmission lines should grow no higher than 10 feet to ensure that overgrown plants do not interfere with service lines and threaten power disruptions.

PHOTO: A ComEd employee examines a plant in the field, open plant ID book in his hand.
A ComEd employee does some plant identification in the field.

In 2010, ComEd turned to the Chicago Botanic Garden for help in managing the overgrown narrow leaf cattail, reedy phragmites, common and glossy buckthorn, and other invasive species. “We reached out to the Chicago Botanic Garden as a partner to research the transmission corridor and see, over time, with different maintenance practices, what would come back,” said Kevin Jury, senior project manager for vegetation management at ComEd. “We wanted to use the information to guide our practices and see if there was something we could tweak in our process to reap an economical benefit and a benefit for the environment.”

As a result, the Garden developed a pilot program to research ways to turn overgrown corridors into sustainable native landscapes. “We’re interested because ComEd is the second-largest landowner in the state, and improving the habitat could have a major impact on the whole region,” said Greg Mueller, chief scientist and Negaunee Foundation vice president of science at the Garden. “It fits the type of public-private partnership that allows companies like ComEd to be better stewards of their land and allows the Chicago Botanic Garden access to land for use as a research opportunity.”

PHOTO: Michigan lilies (Lilium Michiganense)
Michigan lilies (Lilium michiganense)

Now, in the program’s third year, plant life abundant nearly 200 years ago has reemerged with surprising vigor. Tall stalks of scouring rush—the same kind used by prairie homesteaders to scrub pots and pans—are growing under power lines alongside bright red cardinal flowers (Lobilia cardinalis), orange-petalled Michigan lilies (Lilium michiganense), and eastern prairie fringed orchids (Platanthera leucophaea).

Nearly 300 different plant species, including 225 native species and 40 newly identified species, have been recorded on six research plots. The plots are bounded by transmission towers and divided into three experimental conditions: two sites receive annual spot treatment with diluted herbicide solutions that control broad-leaved plants but protect grasses; two receive prescribed burnings every two to three years; and two sites are left unmanaged as experimental controls.

In addition to the current research sites at the state park, two new research locations are underway in Vernon Hills and Highland Park.

PHOTO: ComEd employees use a frame built of PVC pipe to measure a number of plants in a given square foot of prairie.
Two ComEd employees measure square-foot growth in the prairie.

When the research is finalized in 2016, the Garden, ComEd, and the Illinois Department of Natural Resources aim to implement the most effective approaches in ComEd’s ongoing maintenance of 3,000 corridor right-of-way miles and 5,300 miles of power lines throughout northern Illinois. “The lasting impact of this partnership will reintroduce, protect, and enhance native ecosystem locations throughout northern Illinois,” Mueller said. “We are hopeful the lessons learned from this collaboration can one day serve as a road map on how a groundbreaking public-private partnership can protect natural habitats beyond northern Illinois.”

Visit the Garden for World Environment Day on Saturday, June 7, and discover how you can make an impact in restoration and conservation.

This post was adapted from an article by Jeff Link that appeared in the winter edition of Keep Growing, the member magazine of the Chicago Botanic Garden.

©2014 Chicago Botanic Garden and my.chicagobotanic.org

Elevating the Prairie

Early to mid-June is the greenest and lushest time in our experimental and ever-changing Green Roof Garden, one of the few rooftop landscapes in the area that invites the public in for a visit.

The Green Roof Garden is at is lushest in mid-June.
Native plants create a prairie-like effect atop the Plant Science Center.

Now in its fourth growing season, the 16,000-square-foot garden creates an oasis atop the Daniel F. and Ada L. Rice Plant Conservation Science Center. The green expanse helps reduce rainwater runoff and insulate the building from heat and cold. The garden also serves as living laboratory under the stewardship of Richard Hawke, plant evaluation manager.

“This is so new to us. We didn’t know what to expect. It’s been a complete learning process,” said Hawke, who has evaluated nearly 230 types of plants each year since the fall of 2009.  “We want to keep testing and trying and increasing the palette each year.”

Hawke has watched nature take a hand in creating a pleasing meadow effect across the less formal Ellis Goodman Family Foundation Green Roof Garden South. “More people are drawn to this than ever,” Hawke said. “It’s just become a true landscape.”

The skyblue aster (Symphyotrichum oolentangiense) is “finally established and starting to do its own thing,” he said, and flowering for the first time are the dwarf false indigo (Amorpha nana) and largeleaf wild indigo (Baptisia alba var. alba). The latter takes its time in a landscape, first putting down a taproot—hard to do in eight inches of growing medium! Once established, it sends up a tall spike of showy, white flowers that bloom for several weeks. Like other members of the bean or legume family, wild indigo improves the soil by increasing its nitrogen levels.

aquilegia canadensis
Wild columbine (Aquilegia canadensis)

The deep coral native columbine (Aquilegia canadensis) is beginning to spread, blending into the lavender and white blooms of the hairy beardtongue (Penstemon hirsutus) and foxglove beardtongue (Penstemon digitalis) growing nearby. Bright yellow lanceleaf coreopsis (Coreopsis lanceolata) and the silvery, feathery foliage of field sagewort (Artemisia campestris ssp. Caudate) add to the prairie aesthetic with their layered colors and textures.

Foxglove beardtongue (Penstemon digitalis)
Foxglove beardtongue (Penstemon digitalis)

The more formally planted Josephine P. & John J. Louis Foundation Green Roof Garden North features wavy patches of sedums, a popular rooftop variety, alternating with familiar cultivars of plants. Flowering bulbs bring the garden into color in early spring. Mourning doves, robins, swallows, mallards, Baltimore orioles, and purple finches count among its bird visitors.

Evaluations of perennial plants typically take four years, but Hawke is sensing that it may take more time than that to tease out the “best that can be grown on a rooftop.” Prairie dropseed (Sporobolus heterolepis) has proved to be the top-performing grass, providing an elegant fine texture and remaining dark green even in the worst of last summer’s drought. Some plants have thrived, others have merely survived, and others have all but disappeared from the landscape over the evaluation period. Hawke has learned, for example, that the pale purple coneflower (Echinacea pallida) is doing better than the more commonly known purple coneflower (Echinacea purpurea). Yarrow is not doing as well as he expected, but prostrate junipers show promise. “Our goal was to learn everything we possibly could about growing plants on a green roof,” he said. “I still think there’s a lot more to learn.”


©2013 Chicago Botanic Garden and my.chicagobotanic.org