Ageratina altissima (L.) King & H. Rob.
Asteraceae (Aster Family)
USDA Symbol: AGAL5
Solitary or clustered firm stems bear flat-topped clusters of small fuzzy white flower heads composed entirely of disc flowers.
This plant used to be placed in the genus Eupatorium, as did Smaller White Snakeroot (A. aromatica), a nonaromatic plant despite its name; it has less coarsely toothed leaves, the upper ones stalkless. Other similar species are Late-flowering Thoroughwort (Eupatorium serotinum), which has long-stalked lanceolate leaves with 3-5 main veins, and Hyssop-leaf Thoroughwort (E. hyssopifolium), with very narrow leaves in whorls of 3-4.
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Plant CharacteristicsDuration: Perennial
Size Notes: Up to about 4 feet tall, often shorter.
Fruit: Fruit is a cypsela (pl. cypselae). Though technically incorrect, the fruit is often referred to as an achene.
Bloom InformationBloom Color: White
Bloom Time: Jul , Aug , Sep , Oct , Nov
DistributionUSA: 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
Canada: NB , NS , ON , SK
Native Distribution: S. Ontario to New Brunswick; south through New England to Virginia and upland Georgia; west to Louisiana and ne. Texas; north to Wisconsin.
Native Habitat: Woods and thickets.
Growing ConditionsWater Use: Low
Light Requirement: Sun , Part Shade
Soil Moisture: Dry , Moist
Drought Tolerance: High
Conditions Comments: Prefers full sun but will tolerate shade in more southern locations.
Value to Beneficial InsectsSupports Conservation Biological Control
This information was provided by the Pollinator Program at The Xerces Society for Invertebrate Conservation.
National Wetland Indicator Status
BibliographyBibref 875 - Armitage's Native Plants for North American Gardens (2006) Armitage, A. M.
Bibref 946 - Gardening with Prairie Plants: How to Create Beautiful Native Landscapes (2002) Wasowski, Sally
Search More Titles in Bibliography
Web ReferenceWebref 3 - Flora of North America (2014) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Additional resourcesUSDA: Find Ageratina altissima in USDA Plants
FNA: Find Ageratina altissima in the Flora of North America (if available)
Google: Search Google for Ageratina altissima
MetadataRecord Modified: 2022-10-06
Research By: TWC Staff