Native Plant Trust

Ageratina altissima

white snakeroot (Eupatorium rugosum)

Ageratina is a striking summer bloomer, with fuzzy white flowers clustering towards the tips of the racemes. This species naturalizes readily and can be aggressive in sunny, moist spots, so make sure to site it accordingly. Particularly great for native bees!



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Height: 24-36 in
Spread: 24-36 in
Hardiness Zone: 4-9


Bloom Color: White

Characteristics & Attributes

Cultivation Status
Species
Exposure
Sun
Part Shade
Soil Moisture
Wet
Average
Ecoregion
(83) Eastern Great Lakes Lowlands
(59) Northeastern Coastal Zone
(84) Atlantic Coastal Pine Barrens
(82) Acadian Plains and Hills
(58) Northeastern Highlands
Ornamental Interest
Fall Bloom
Summer Bloom
Attracts Wildlife
Other Pollinators/Wildlife
Attracts Bees
Attracts Butterflies
Tolerance
Deer/Rabbit Resistant
Additional Attributes
Low Maintenance
Fragrant
Landscape Use
Rain Garden
Naturalize
Growth Habit
Spreading/Suckering


North American Distribution


General Description

Bloom Description: Lacking ray flowers, this sunflower family plant only has disc flowers in its composite flat-topped flower clusters. Tiny individual flowers are packed in corymbs 3-4" wide. The bright white flowers brighten up shady areas in August, September, and October.

Growth Habit & Shape: White snakeroot has coursely toothed, oval shaped, opposite deep green leaves on upright stems. Bushy and lush, plants start off in their own distinguishable clumps, and over time they spread by rhizomes and seed to form colonies.

Soil Preferences: Average to moist and humusy soils. Tolerates dry soils, but prefers moist.

Root Description: Rhizomatous spreader

Garden Uses: Wildlife gardens, cottage gardens, shade gardens, rain gardens and naturalized areas.

Best Management & Maintenance: To avoid undesireable reseeding cut back spent flower heads before they go to seed.

Common Problems: Leaf minors and flea beetles occaisonally attack the leaves.

Benefits

Ornamental Value:

Wildlife Benefits: The flowers attract bees, butterflies and moths for late season forage. A larval host plant for the caterpillars of clymene moth, Leucospilapteryx venustella, dusky groundling, and hitched arches.

Other Practical/Environmental Benefits: A great plant for use in bioretention basins, rain gardens, and waterwise gardens. Drought tolerant.

Use in place of: Chrysanthemum grandiflorum (ornamental mum)

Ecology

Habitat:
Rocky woodland edges, openings, recently disturbed shaded sites, and moist thickets.


Response to Disturbance: Will reseed readily and spread by rhizome in recently disturbed soils, becoming slightly aggressive especially if there is access to ample moisture and light. In less favorable conditions, such as more established soils in dry shade, white snakeroot will colonize less and allow other plants to grow in the same space with it.

Native State Distributions:
Canada: CA: NB, NS, ON, QC, SK
USA: US: AL, AR, CT, DC, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, ND, NE, NH, NJ, NY, OH, OK, PA, RI, SC, SD, TN, TX, VA, VT, WI, WV


Wetland indicator status: FACU

Companion Plants:
Solidago flexuosa (zigzag goldenrod), Geranium maculatum (wild geranium), Zizia aurea (golden Alexanders), Helianthus divaricatus (woodland sunflower), and Sambucus racemosa (red elderberry)

References

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white snakeroot - Ageratina altissima from Native Plant Trust
Photo by Dan Jaffe (c) Native Plant Trust
white snakeroot - Ageratina altissima from Native Plant Trust
Photo by Dan Jaffe (c) Native Plant Trust