Botanizing From Behind the Wheel

It’s May again, and that field on your way to work is covered in tiny yellow flowers, just like it was this time last year. You can’t take your eyes off the road long enough to get a good look at the individual blossoms, but you’d sure like to know what they are.

“That’s why we wanted to offer a free roadside wildflowers booklet,” said Missouri State Botanist Malissa Briggler. She’s talking about an MDC publication published in 2023. 

Briggler said the value of A Guide to Missouri’s Roadside Wildflowers “lies with people who may not think a lot about plants but see a particular flower on their way to work.” She noted that MDC has been providing free online species identification information for a long time (check out mdc.mo.gov/field-guide), but she said that the booklet is an easy-to-use handout drivers can keep in their gloveboxes.

“Just don’t try to use it while you’re driving,” Briggler said. “Find a safe place to pull over and snap a photo with your phone if you don’t have time or can’t get close enough to the blossoms to examine them yourself.”

She said that even a photo shot from middle distance can help you find your flower in the booklet.

Gone in a Flash

In the booklet’s introduction, Briggler noted the challenges of trying to identify blooms when you’re driving.

“Most plant field guides are written with the assumption that the user can closely observe the subject, has an opportunity to look at fine details, and can take their time observing those details,” she wrote. 

“Unlike when we’re trying to identify a bird, fish, snake, etc., we usually do not need to worry about plants ‘getting away.’ Except when we are in a moving car. The plant did not go anywhere, but we sure did. In a flash, our opportunity to identify the plant is over. Botanists have a term for this: windshield botanizing.”

To make windshield botanizing easy, she focused on 25 of the most common flowers drivers are likely to see along Missouri’s roadsides. She also organized them by flower color: white, blue/purple, orange, and yellow, and she listed them next to or near similar-looking flowers as much as possible.

In addition to close-up and windshield-view shots, the book provides clues about Missouri’s main types of natural communities — or habitats. 

“This helps readers understand the connections between individual plants and the places where they can expect to see them,” she said.

For example, the only orange flower listed in the booklet is butterfly milkweed (Asclepias tuberosa). This plant is scattered throughout Missouri, but you can expect to see it in open, dry habitats such as prairies, glades (which resemble rocky mini-deserts), and pastures.

While it’s possible to see most of the booklet’s flowers anywhere in the state, it’s important to know and remember that native plants originated in Missouri’s natural communities, Briggler said. She noted that many of the state’s natural communities — prairies, savannas, glades, and wetlands, for example — have declined since settlement.

“Connecting our beautiful native roadside wildflowers with the prairies, glades, wetlands, and forests they came from can help us better conserve those natural communities,” she said.

Who Planted Those Flowers?

Briggler noted that roadside wildflowers are often opportunistic. They’ve had the chance to grow near roadsides because weather or animals have carried their seeds or roots there, or because they were already in the soil when roads were built.

“On the western side of the state, native prairies were there when the road went through,” said Mark Aufdenberg, senior roadside management specialist for the Missouri Department of Transportation (MoDOT). “You can still see native prairie wildflowers growing along or near those roads.”

He went on to explain MoDOT’s policy for managing 34,000 miles of Missouri roadsides. 

“Statewide, our policy is that any disturbing of the right of way is followed by seeding native plants,” he said. By “disturbing,” Aufdenberg said the policy means construction or a major expansion.

“We plant cool-season grasses immediately along roadsides for sight distance reasons,” he said. “Anything outside of the first 30 foot (from the center of the road) is all native grasses and wildflowers.”

He noted that I-70 has a lot of natives currently, and that the state has funded a major expansion of this economically important artery for the next several years. 

“Whatever is disturbed will be reseeded in natives,” he said.

Aside from MoDOT, many entities and individuals have established native wildflowers along private and public roadsides throughout Missouri. More than 130 of them are Grow Native! professional members. Grow Native! is a marketing and education program of the Missouri Prairie Foundation (MPF). 

“Grow Native! professional members include several Missouri cities and universities as well as numerous nonprofit organizations and native plant businesses,” said MPF Executive Director Carol Davit. She added that they are true conservation heroes. “They are harvesting native seed, growing and selling native plants, designing and stewarding native landscapes, and advocating for and educating about the many benefits of native plants in altered landscapes.”

Not all Blooms are Beneficial

One major force threatening Missouri’s native wildflowers — and the natural communities that give rise to them — is nonnative invasive plants like musk thistle. Once they appear, these plants spread quickly, displacing crops and pasture grasses on farms and native plants in natural communities.

Briggler said that helping readers know what they’re looking at along roadsides gives them the power to identify and control invasive plants on their property. The booklet includes eight nonnative and invasive species readers have most likely seen growing along Missouri roadsides.

To keep invasive plants from moving away from roadsides and into adjoining natural communities, MDC teamed up with MoDOT and MPF to launch the Invasive Species Strike Team. In development for many years, the program began formally in the state’s southeast region in 2020. Since then, “we’ve distributed 28 UTVs (utility task vehicles) to our crews statewide,” said MoDOT’s Aufdenberg. He added that MDC equipped the UTVs with injection sprayers to help field crews use herbicide more efficiently. “It saves on costs and environmental impact,” he said. “Crews can spot spray as much as possible.”

MDC Invasive Species Coordinator Angela Sokolowski agreed. “With such precise sprayers, crews are not leaving behind swaths of dead vegetation. They can select-spray just the invasives, leaving native grasses and wildflowers to reseed. This is really important along the miles of roadsides that border conservation areas.”

MPF’s Davit added that MoDOT’s work to treat invasive plants along the highways under their jurisdiction “is critically important to slow the spread of nonnative, invasive plants that threaten Missouri’s native biodiversity.” She said MPF is pleased to partner with MDC and MoDOT on the program

When and Where to see Roadside Wildflowers

Many of the booklet’s blossoms can appear just about anywhere in the state during their blooming season. Here’s a quick overview of the months and places you can expect to see five of Missouri’s showiest native wildflowers. Consider planning road trips around the bloom times of your favorite wildflowers.

May–July: Pale Purple Coneflower

One of Missouri’s five types of echinacea, the pale purple coneflower (Echinacea pallida) resembles a badminton birdie, with petals that hang down, and long narrow leaves that are mostly at the base of the plant. Associated with prairies, savannas, and glades, the pale purple coneflower is found throughout most of Missouri but is more common on the western side of the state. Pale purple coneflower often appears along roadsides that were planted for highway beautification.

May–August: Missouri Evening Primrose

Missouri evening primrose (Oenothera macrocarpa) is a short plant reaching only 12–18 inches tall. What it lacks in height, it makes up for in floral display. The four bright yellow petals can make a flower the size of a teacup saucer. It is a popular plant for native landscaping and is often included in plantings for roadside beautification. Look for it along the tops of rocky road cuts, especially in the southern part of the state.

May–September: Butterfly Milkweed

One of Missouri’s 20 milkweed species, butterfly milkweed (Asclepias tuberosa) shows up as flashes of orange color that are easy to spot along roadsides. Few other roadside wildflowers with that bright orange color appear during mid-summer when butterfly milkweed is at peak of flowering. Several stems 18–30 inches tall and clustered together can make the plant look like a small bush from a distance. As one might guess, butterflies are attracted to the plant as a nectar source, which makes it a common species in native landscaping and butterfly gardens.

July–October: Prairie Blazing Star

One of nine types of liatris in Missouri, prairie blazing star (Liatris pycnostachya) looks like stands of tall purple spikes. It is also easily identified by the dense arrangement of narrow, grasslike leaves along the stem. Scattered statewide, it can grow up to 5 feet tall, towering over other vegetation growing along roadsides.

August–November: Tall Goldenrod

One of 23 goldenrod species in Missouri, tall goldenrod (Solidago altissima) is usually regarded as a weed that grows abundantly in fallow places. It exhibits extensive underground growth that gives rise to multiple unbranched, leafy stems. Tall goldenrod has yellow flowers at the top of the stem that are grouped in a way that resembles a pyramid. Migrating monarchs and other pollinators depend on tall goldenrods for their readily available nectar in late summer and fall.

Free and Easy to Use

This 8-by-5.5-inch booklet features 25 common species, including native wildflowers and a few widespread invasives like teasel and musk thistle.

The 68-page booklet is available at many MDC locations. Call ahead for availability. Missouri residents may order a free copy from pubstaff@mdc.mo.gov. Provide the publication title and your shipping address. Call 573-522-0108 to order by phone. You can also download an accessible PDF at short.mdc.mo.gov/4Y6.