1. Blue Mistflower

Name: Conoclinium coelestinum (syn. Eupatorium coelestinum)

USDA Hardiness Zones: 5 to 11

Size: Up to 3 feet tall and wide

Conditions: Full sun to partial shade; average, well-drained soil

Blue mistflower grows in ditches all over the Southeast, making it a proven roadside plant. Don’t treat it as a weed, though. Its beautiful blue-purple flowers bloom on stiff stems in mid- to late summer through fall. It spreads by roots but hasn’t misbehaved in my garden, providing just enough divisions to share with others. It also makes a great cut flower to pair with a bit of Queen Anne’s lace (Daucus carota, Zones 3–9).

2. Tennessee Coneflower

Name: Echinacea tennesseensis

Zones: 3 to 9

Size: 2 to 3 feet tall and 2 feet wide

Conditions: Full sun to partial shade; average, well-drained soil

Tennessee coneflower is a rare sight in the wild, but I’ve grown it successfully for several years. It loves the full sun that roadsides offer and is adaptable to a range of conditions. Its dark mauve-pink flowers have upturned, ray-formed petals—very distinct from other coneflowers—and attract visitors and passersby alike. Keep it away from other coneflowers to avoid cross-pollination.

3. Maximilian Sunflower

Name: Helianthus maximiliani

Zones: 4 to 9

Size: Up to 10 feet tall and 4 to 5 feet wide

Conditions: Full sun; average, well-drained soil

Maximilian sunflower is often found growing in roadside areas, in open fields, and along fencerows from Canada to Texas. Its hardy, fibrous root system will form colonies of bright, sunny yellow blooms in summer, providing plenty of pollen for butterflies and bees. Its seeds are a paradise for goldfinches. Though tall and floppy in the wind, plants can be managed by cutting them halfway down in early summer.

4. White Beardtongue

Name: Penstemon digitalis

Zones: 3 to 8

Size: 2 to 4 feet tall and 1 to 2 feet wide

Conditions: Full sun to partial shade; average, well-drained soil

White beardtongue is a tough, long-lived perennial. It’s native to many areas in the United States, but the plants in my garden were brought here by my father from a plant- and rock-buying trip to Arkansas. He transplanted a few plants in the yard and then scattered some seeds. Now, 40 years later, a beautiful stand of white flowers bloom on stiff, tall stems in late May and early June. White beardtongue transplants well in most gardens but also grows well in containers.

Photos: (1 and 4), Jerry Pavia; (2), Bill Johnson; (3), courtesy of Jeff McMillian, USDA-NRCS Plants Database