Eltrot Heracleum sphondylium
Eltrot is an introduced perennial herb, found in Canada and the lower 48 states. It grows to 3 ft and blooms Apr – Jul.
More about this plant
Heracleum sphondylium, commonly known as hogweed or common hogweed, is a herbaceous perennial plant in the carrot family Apiaceae, which includes fennel, cow parsley, ground elder and giant hogweed. It is native to most of Europe, western Asia and northern Africa, but is introduced in North America and elsewhere. Other common names include cow parsnip. The flowers provide a great deal of nectar for pollinators. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 5 derived from its U.S. range
- Height
- 3 ft
- Lifespan
- Perennial
- Foliage
- Broadleaf
- 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 ~8 caterpillar species
Heracleum supports ~8 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 modest genus.
Recorded feeding on Heracleum in North America, including:
✦ Bees 118 bee visitors
118 native & managed bee species are documented visiting Eltrot — the 12 most-recorded:
Wildlife & visitors 53 birds · 43 nectaring
Open records of who else uses Eltrot — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 53 birds species (fruit, seed, browse) — the most-recorded:
43 adult butterfly & moth species are recorded nectaring at its flowers — the most-recorded:
Related plants
More Heracleum →
How we know this (4) Methods & honest limits
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.
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.
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 (27) 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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