Yankeeweed Eupatorium compositifolium
Yankeeweed is a perennial wildflower native to the lower 48 states. It blooms Oct – Nov.
More about this plant
Eupatorium compositifolium, commonly called yankeeweed and coastal dog fennel, is a North American herbaceous perennial plant in the family Asteraceae native to the southern United States. Like other members of the genus Eupatorium it has inflorescences containing a large number of small, white flower heads, each with 5 disc florets but no ray florets. The plant is 0.5 to 2 meters tall. Flowers bloom August to October. Its habitats include sand dunes, disturbed areas, and flat-woods. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 7 derived from its U.S. range
- Lifespan
- Perennial
- Flower colour
- White AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~41 caterpillar species
Eupatorium supports ~41 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a strong genus.
Recorded feeding on Eupatorium in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees 3 bee visitors
3 native & managed bee species are documented visiting Yankeeweed :
Wildlife & visitors 1 nectaring
Open records of who else uses Yankeeweed — a generalist food-web signal, kept separate from the keystone Ecological Value.
1 adult butterfly & moth species is recorded nectaring at its flowers:
Across 189 U.S. vegetation-survey plots that recorded Yankeeweed, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.
Related plants
More Eupatorium →
How we know this (2) Methods & honest limits
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.
Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.
Sources for this entry (21) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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