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White Snakeroot Eupatorium rugosum

Other Common Name(s):

Other plants called White Snakeroot:

Previously known as:

  • Ageratina altissima
Phonetic Spelling
yoo-pah-TOR-ee-um roo-GOH-sum
This plant has high severity poison characteristics.
See below
Description

Eupatorium rugosum, or White Snakeroot is a herbaceous perennial that can grow to 3 feet. The plant is native to woodland areas in the Eastern United States and typically occurs in rich or rocky woods, thickets, wood margins, and rocky areas. Garden uses include cottage gardens, wild gardens, woodland gardens, and naturalized areas. It may also be effective in shady corners of the border.  

White Snakeroot is easily grown in average, medium to wet, well-drained soils in full sun to part shade. While it does well in dry soil, it prefers part shade in moist, organic soils. These plants have decidedly better shade tolerance than most other species of Eupatorium. The 'Chocolate' cultivar has purple leaves throughout the summer. This is one of the last wildflowers to bloom during the fall.

The root system consists of spreading rhizomes and shallow fibrous roots. This plant can spread by means of its rhizomes, or it can reseed itself into new areas. Because it spreads easily by seed, you should deadhead spent flower heads to avoid any unwanted self-seeding. 

Reportedly, the erroneous belief that an extract of the roots was a remedy for snakebite led to the common name. However, settlers who drank milk from cows that fed on this plant often developed the disease called milk sickness. See information below for toxicity. 

Diseases, Insects and Other Plant Problems:

The plant is susceptible to leaf miners and flea beetles may attack the foliage. Under optimum growing conditions, the plant can spread rapidly through self-seeding and rhizomes. Full sun in a dry situation can cause the leaves to turn yellow and wilt

Cultivars / Varieties:
Tags:
#showy flowers#deciduous#poisonous#perennial#wildlife plant#food source#NC native#native garden#native wildflower#wildflower garden#food source fall#food source herbage#food source nectar#food source pollen#bird friendly#food source hard-mast fruit#butterfly friendly#FACU Piedmont Mountains#FACU Coastal
 
Cultivars / Varieties:
Tags:
#showy flowers#deciduous#poisonous#perennial#wildlife plant#food source#NC native#native garden#native wildflower#wildflower garden#food source fall#food source herbage#food source nectar#food source pollen#bird friendly#food source hard-mast fruit#butterfly friendly#FACU Piedmont Mountains#FACU Coastal
  • Attributes:
    Genus:
    Eupatorium
    Species:
    rugosum
    Family:
    Asteraceae (Compositae) - Aster or Sunflower Family
    Life Cycle:
    Perennial
    Recommended Propagation Strategy:
    Division
    Seed
    Country Or Region Of Origin:
    Native to woodlands in Eastern United States
    Wildlife Value:
    Flowers are attractive to butterflies, especially smaller species, and other pollinators, including leaf-cutting bees. Songbirds eat the seeds.
    Edibility:
    Toxic
    Dimensions:
    Height: 1 ft. 0 in. - 3 ft. 0 in.
    Width: 2 ft. 0 in. - 4 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Herb
    Native Plant
    Perennial
    Poisonous
    Wildflower
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Ascending
    Clumping
    Erect
    Maintenance:
    Low
  • Cultural Conditions:
    Light:
    Deep shade (Less than 2 hours to no direct sunlight)
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    Clay
    Loam (Silt)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    Available Space To Plant:
    3 feet-6 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
  • Fruit:
    Fruit Color:
    Black
    Display/Harvest Time:
    Fall
    Fruit Type:
    Achene
    Fruit Length:
    < 1 inch
    Fruit Description:
    During autumn, each disk floret in a flowerhead is replaced by an achene with a small tuft of white hairs. These achenes are about 1/10 of an inch long, narrowly oblongoid in shape, 5-ribbed, and black; they are distributed by the wind.
  • Flowers:
    Flower Color:
    White
    Flower Inflorescence:
    Corymb
    Panicle
    Flower Value To Gardener:
    Fragrant
    Long Bloom Season
    Showy
    Flower Bloom Time:
    Fall
    Summer
    Flower Size:
    3-6 inches
    Flower Description:
    Small fluffy bright white flowers (composites with rays absent) atop smooth stems typically rising 3-5’ tall. It blooms from late summer to frost. The upper stems terminate in compound corymbs or flat-headed panicles of flowerheads that span 2 to 6 inches across. Each flowerhead is about ½" across and contains 10-30 disk florets that have brilliant white corollas and styles. There are no ray florets. Each small disk floret consists of a small tubular corolla with 5 lobes that are spreading and pointed and a divided style that is strongly exerted from the corolla. At the base of each flowerhead, there is a single series of linear floral bracts that are light green and non-overlapping. The blooming period lasts about 2 months for a colony of plants.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Green
    Leaf Feel:
    Prickly
    Leaf Type:
    Needles
    Leaf Arrangement:
    Opposite
    Leaf Shape:
    Cordate
    Lanceolate
    Ovate
    Leaf Margin:
    Crenate
    Serrate
    Hairs Present:
    No
    Leaf Length:
    3-6 inches
    Leaf Description:
    White snakeroot leaves have long, nettle-like, stalks. The leaf shape ranges from lance like to elliptic-oval. The 3 to 6 inch leaves are paired along the stems and become smaller as they ascend the stems. The lower leaves are cordate to cordate-ovate, while the upper leaves are broadly lanceolate to lanceolate. All of the leaves are largely hairless and strongly serrated-crenate along their margins; they are medium to dark green on their upper surfaces and light green on their lower surfaces. There are 3 prominent veins on the upper surface of each leaf (particularly the lower ones), while the lower surface has an elevated network of veins.
  • Stem:
    Stem Color:
    Brown/Copper
    Green
    Stem Is Aromatic:
    No
    Stem Form:
    Straight
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    The light green to tan stems are terete and hairless (or nearly so). Stems are upright and tall.
  • Landscape:
    Landscape Location:
    Woodland
    Landscape Theme:
    Butterfly Garden
    Pollinator Garden
    Rain Garden
    Shade Garden
    Water Garden
    Attracts:
    Butterflies
    Pollinators
    Songbirds
    Resistance To Challenges:
    Deer
    Problems:
    Poisonous to Humans
  • Poisonous to Humans:
    Poison Severity:
    High
    Poison Symptoms:
    The plant is highly toxic and may be fatal if eaten. Toxicity is characterized by weakness, nausea, abdominal pain, vomiting, delirium, prostration and, eventually, coma.
    Poison Toxic Principle:
    Tremetone, a ketone, and glycosides
    Causes Contact Dermatitis:
    No
    Poison Part:
    Flowers
    Leaves
    Roots
    Sap/Juice
    Seeds
    Stems