Tall Thoroughwort
Eupatorium altissimum
- Native to:
- Canada, United States
iNaturalist: © adriennea (iNaturalist #93088595)
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Asteraceae
- Genus:
- Eupatorium
- Species:
- Eupatorium altissimum
- USDA Symbol:
- EUAL3
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Forb/herb
- Height:
- 200 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- High
- Bloom Months:
- aug,sep,oct
- Bloom Colors:
- white
Wildlife Benefits
- Bees:
- ★☆☆☆☆ Documented bee visitation (GBIF)
- Butterflies & Moths:
- ★☆☆☆☆ Documented Lepidoptera association (GBIF)
- Caterpillars:
- ★☆☆☆☆ Recorded caterpillar host plant (HOSTS Database)
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★☆☆ Butterfly & moth species supported by this genus (NWF)
Host Plant for Caterpillars
Three-lined Flower Moth (Schinia trifascia)
Reported Fauna Sightings
Bees: Brown-belted bumble bee (Bombus griseocollis), Common eastern (Bombus impatiens), Eastern Carpenter Bee (Xylocopa virginica), Southern plains bumble bee (Bombus fraternus)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, moths, wasps
- Deer Resistant:
- Yes
- Fire Ecology:
- Fire adapted — tolerates or benefits from fire
- Fire Notes:
- Resprouts from rootstock following fire; commonly found in fire-maintained prairies and savannas.
Soil Requirements
- Soil Type:
- well-drained, sandy or rocky soil
- pH:
- 6.0 - 7.5 (slightly acidic to neutral)
- Drainage:
- excellent drainage required
- Moisture:
- dry to moderate
- Notes:
- prefers open, sunny areas with poor soil
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 30–60 days
- Germination Time:
- 14–30 days
- Notes:
- Seeds require light for germination; surface sow and do not cover.
The above propagation data sourced from Claude AI
Pre-treatment: Seed is planted into round cell greenhouse flat liners with 38 cells per flat that have been filled with coarse processed bark and composted pine bark growing medium. Seed is surface sown at a rate of 3-5 seeds per cell and lightly covered with starter sized, 1/16" - 1/8" diameter, granite poultry grit to combat damping off diseases. Prepared flats are lightly hand watered to slightly moisten the growing medium and cold stratified at 35 degrees Fahrenheit for a minimum of 21 days.
Source: npn.rngr.net