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Asteraceae family

Hemp Agrimony Eupatorium cannabinum

Hemp Agrimony is an introduced perennial herb, found in Canada and the lower 48 states. It grows to 1.9 ft.

More about this plant

Eupatorium cannabinum, commonly known as hemp-agrimony, is a herbaceous plant in the family Asteraceae. It is a robust perennial native to Europe, Northwestern Africa, Turkey, Syria, Iran, Iraq, Jordan, the Caucasus and Central Asia, and grows in damp to wet habitats, usually in lowlands but known up to 410 m altitude in Britain. It is cultivated as an ornamental plant and occasionally found as a garden escape in scattered locations in China, the United States and Canada. It is extremely attractive to butterflies, much like buddleia. Wikipedia →

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
Cold hardiness (derived) — Hardiness
Hardiness
≥ zone 7 derived from its U.S. range
Size & form
Sources · Size & form
TRY Plant Trait Database (CC BY 4.0) — Height · Foliage
USDA PLANTS — Lifespan
McKenzie et al. 2025 — community-science image analysis (MIT) — Flower colour
Height
1.9 ft
Lifespan
Perennial
Foliage
Broadleaf
Flower colour
Pink AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
In the garden
Herb layer — Sits in the herb of a layered food forest or polyculture.Open guide →
Chop-and-drop biomass — Soft, low-density wood is quick-growing and easy to cut back — coppice it and drop the trimmings in place as mulch.Open guide →
derived roles
AI = read by an AI vision model · DERIVED = a computed estimate, not a direct measurement. The “How we know this” section below details each.
Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

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.

Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
✦ Bees 113 bee visitors
Wildlife & visitors 92 nectaring

Open records of who else uses Hemp Agrimony — a generalist food-web signal, kept separate from the keystone Ecological Value.

Interaction records (observations, not exhaustive) from GloBI → (CC0). Counts are distinct species; names are the most-recorded. Common names from Wikidata (CC0).
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
How we know this (3) Methods & honest limits
Leaf build Direct fact

We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.

Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.

Díaz, S. et al. (2022) The global spectrum of plant form and function: enhanced species-level trait dataset. Scientific Data 9:755.
Photosynthesis Direct fact

A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.

Kattge, J. et al. TRY plant trait database — Categorical Traits Dataset (2012).
Flower colour Derived

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.

McKenzie, P., Berardi, A.E., Hopkins, R. (2025). flower_color_phenology (MIT).
Derived values are computed from open data by a published method — labelled, cited, and never shown as a direct observation. Full methodology →
Sources for this entry (23) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[05] Invasive / introduced status — US-RIIS v2.0 (USGS)
[07] Description — Wikipedia (CC BY-SA)
[08] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[11] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[12] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[13] Cold hardiness (derived) — Derived from U.S. range × USDA PHZM zones
[14] Wildlife & visitors — GloBI — Global Biotic Interactions (CC0)
[20] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[21] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[22] Caterpillar species — NHM HOSTS (CC0)
[23] County range — GBIF Open Data — open-licensed occurrences (CC0/CC-BY) → county
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
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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