Species Native to Missouri
Common Name: white snakeroot
Type: Herbaceous perennial
Family: Asteraceae
Native Range: North America
Zone: 3 to 8
Height: 3.00 to 5.00 feet
Spread: 2.00 to 4.00 feet
Bloom Time: September to frost
Bloom Description: White
Sun: Full sun to part shade
Water: Medium to wet
Maintenance: Medium
Suggested Use: Naturalize, Rain Garden
Flower: Showy
Attracts: Butterflies
Tolerate: Deer
Culture
Easily grown in average, medium to wet, well-drained soils in full sun to part shade. Prefers part shade in moist, humusy soils. Does reasonably well in dryish soils however. These plants have decidedly better shade tolerance than most other species of Eupatorium. Deadhead spent flower heads to avoid any unwanted self-seeding. Easily grown from seed.
Noteworthy Characteristics
Ageratina altissima commonly called white snakeroot, is native to woodland areas in the Eastern United States. It is common throughout Missouri where it typically occurs in rich or rocky woods, thickets, wood margins and rocky areas (Steyermark). It features small fluffy bright white flowers (composites with rays absent) arranged in loose, flattened clusters (corymbs to 3-4” across) atop smooth stems typically rising 3-5’ tall. Blooms from late summer to frost. This is a somewhat weedy perennial that can spread aggressively by rhizomes and self-seeding. Long-stalked, sharp-toothed, taper-pointed, lance-shaped to elliptic-oval, nettle-like, dark green leaves (3-6” long) are paired along the stems. Native Americans reportedly used a decoction of the roots as a remedy for snakebite, hence the common name. Settlers who drank milk from cows that fed on this plant often developed the disease called milk sickness. This plant is synonymous with Eupatorium rugosum.
Specific epithet means tall or highest.
Problems
No serious insect or disease problems. Leaf miners and flea beetles may attack the foliage. Self-seeding and rhizomatous can spread rapidly in optimum growing conditions.
Uses
Cottage gardens, wild gardens, woodland gardens and naturalized areas. May be effective in shady corners of the border.