Roadside Wildflowers

• Passengers spot. Drivers drive.

  This guide is for the person in the passenger seat. Eyes on the road if you are behind the wheel.

• Look for streaks, not hairs.

  Color, height, and where the color sits on the plant do the work. The tiny details stay with the people who kneel.

• Yellow means “probably.”

  Plenty of entries admit their closest lookalike is basically anything else yellow. Confidence is the main tool.

All 25 photos from the book

The mystery smear deck

Every photograph in the guide, face down. Try to guess first, then flip for the parked photo, the name, the season, and the one tip that actually helps at 70 mph.

Showing 25 of 25

• Mystery smear · p. 3Flip to see it parked Butterfly milkweed Asclepias tuberosa June and July Few wildflowers are orange, so look for striking orange streaks over dark green leaves. Tall orange lilies look similar but are far less common. Orange on a road trip is a gift. Passengers, announce it.
• Mystery smear · p. 4Flip to see it parked Western wallflower Erysimum capitatum Spring and early summer A biennial mustard, 1-2 ft tall, common on dry western roadsides, especially after recent road construction. Easy to mix up with other yellow mustards. Early, yellow, everywhere. Congratulations, you identified “a mustard.”
• Mystery smear · p. 5Flip to see it parked Prairie ragwort Packera plattensis Early summer Large colonies along gravel roads and mowed edges. Look for subtle orange streaks in the yellow, and white smears once seed production starts. Gravel roads buy you a few extra seconds. Use them wisely.
• Mystery smear · p. 6Flip to see it parked Common St. John’s-wort Hypericum perforatum Summer Invasive and spreading west. A pale, cool yellow, intermixed with green because flowers sit at all heights. Bird’s foot trefoil is yellow too, but hugs the ground. Cool-toned yellow, mixed with green. Invasive and unbothered.
• Mystery smear · p. 7Flip to see it parked Upright yellow coneflower Ratibida columnifera Summer Dark cones ride above the yellow petals, so the brown streak sits on top. Stands 1-2 ft; the taller grayhead coneflower takes over further east. A yellow smear wearing a brown hat.
• Mystery smear · p. 8Flip to see it parked Black-eyed Susan Rudbeckia hirta Summer Brown stripes with yellow above and below them, in dense colonies or scattered singles. Usually 1-2 ft tall, often in wet sites. Brown stripes sandwiched in yellow. Club sandwich at 70.
• Mystery smear · p. 9Flip to see it parked Fourpoint evening primrose Oenothera rhombipetala Summer A biennial that explodes in the year or two after drought, construction or other disturbance. Yellow at the tops of plants, mostly on sandy soils in the southern Great Plains. Year one: leaves. Year two: absolutely showing off.
• Mystery smear · p. 10Flip to see it parked Entire-leaved rosinweed Silphium integrifolium Summer Resembles a sunflower but isn’t one. Orange streaks among the yellow, 3-4 ft tall, with yellower-green leaves than Maximilian sunflower. Looks like a sunflower. Files its paperwork as a rosinweed.
• Mystery smear · p. 11Flip to see it parked Maximilian sunflower Helianthus maximiliani Late summer, early fall Orange smears mixed into the yellow, bluish-green foliage, and a 4-5 ft frame. Roads departments love it for its late-season blooms. The tall one every roads department adores.
• Mystery smear · p. 12Flip to see it parked Annual sunflower Helianthus annuus (and H. petiolaris) Summer, especially late summer Tall, dark-centered flowers, often where construction has happened recently. Taller and later than black-eyed Susan; plains sunflower is shorter and loves sandy soil. Big, dark-centered, and always the tallest at the party.
• Mystery smear · p. 13Flip to see it parked Curly cup gumweed Grindelia squarrosa Late summer An annual of disturbed ground, often on the inside edges of cattle fences. Quarter-sized flowers at many heights make lots of narrow yellow streaks. Loves bare dirt. Cattle fences are its whole social scene.
• Mystery smear · p. 14Flip to see it parked Canada goldenrod Oligoneuron canadensis Late summer, early fall Pyramid-shaped yellow tops on 3-4 ft plants make broad yellow bands over green. Broader than stiff goldenrod’s bands. Yellow pyramids on a green stalk. Goldenrod’s whole personality.
• Mystery smear · p. 15Flip to see it parked Stiff goldenrod Oligoneuron rigida Late summer, early fall Flat-topped flowers make narrower yellow bands than most goldenrods, with no dark streaks to suggest a sunflower. Flat tops, skinny bands. The goldenrod that stayed in its lane.
• Mystery smear · p. 16Flip to see it parked Dame’s rocket Hesperis matronalis Spring A non-native, invasive in wooded areas. Tall and vibrantly pink-purple, a once-popular roadside seed mix. No other spring flower matches it. Zero lookalikes. Tall, loud, and not supposed to be there.
• Mystery smear · p. 17Flip to see it parked Shell-leaf penstemon Penstemon grandiflorus Early summer Pink to bluish-pink flowering stalks in large colonies on dry western soils, over pale bluish leaf smears. In full bloom, nothing else even tries.
• Mystery smear · p. 18Flip to see it parked Lead plant Amorpha canescens Early summer A woody plant that grows in big clumps. Dark purple flowers against grayish-green leaves are fairly unique in early summer. Dark purple flowers, gray-green leaves. Moody. Woody.
• Mystery smear · p. 19Flip to see it parked Wild bergamot Monarda fistulosa Summer Also called bee balm. Streaks of pink above pale yellowish-green leaves, often with large butterflies adding accent colors. Pink streaks, pale green backdrop, butterflies as accessories.
• Mystery smear · p. 20Flip to see it parked Purple loosestrife Lythrum salicaria Summer Invasive in wetlands. Dark magenta-pink smears, 3-5 ft tall, in low wet roadsides near bridges and creeks. Gayfeather is the usual mix-up. Magenta, tall, and a little too fond of bridges.
• Mystery smear · p. 21Flip to see it parked Gayfeather / Blazing star Liatris lancifolia (also L. pycnostachya and L. spicata) Summer Broad pink bands on tall plants, in colonies. The narrow stalks below the blossoms stay visible even at fairly high speeds. Several species, one unbothered pink smear.
• Mystery smear · p. 22Flip to see it parked Ironweed Vernonia sp. Late summer Compressed streaks of dark purple above dark green, on 3-5 ft plants. New England aster looks similar but blooms even later. Compact purple streaks. Late summer’s serious flower.
• Mystery smear · p. 23Flip to see it parked Pitcher sage Salvia azurea Late summer, early fall A blue standout among tall late-season flowers, 4-6 ft in sites within five years of construction. Chicory is blue too, but shorter and finished earlier. The blue one. In a field of yellow, you’ll notice.
• Mystery smear · p. 24Flip to see it parked Fleabane Erigeron sp. Summer Tiny white streaks, sometimes tinged pale pink, from an abundance of small flowers. Several close relatives, and few people care which is which. Tiny white smears. Nobody is asking which species.
• Mystery smear · p. 25Flip to see it parked Yarrow Achillea millefolium Summer Flat-topped white flowers form narrow streaks above pale green, 1-2 ft tall. No yellowish centers, unlike asters and daisies. White flat tops, no yellow centers. That’s the whole trick.
• Mystery smear · p. 26Flip to see it parked Mentzelia Mentzelia sp. Summer Mostly in far western Nebraska, Kansas and other Great Plains states. Sunburst-shaped blossoms give the white bands a slightly spiky look. White sunbursts. The smear gets a little spiky.
• Mystery smear · p. 27Flip to see it parked Rattlesnake master Eryngium yuccifolium July and August Tall, along the eastern edge of the Great Plains into Illinois and Indiana. Round flower heads at the very top are distinctive even at speed. Round white heads, way up high. Actual shape recognition at 70.