Milkflower Willowherb Epilobium lactiflorum
Milkflower Willowherb is a perennial wildflower native to Alaska, Canada, and Greenland. It blooms Jun – Aug.
More about this plant
Epilobium lactiflorum is a species of willowherb known by the common name milkflower willowherb or whiteflower willowherb. This plant is found throughout northern North America and northern Eurasia, where it most often grows in moist, rocky areas at some elevation. It is a hairy, clumping perennial with thin stems reaching 10 to 50 centimeters in height, and leafy stolons. The leaves are 2 to 5 centimeters long and have hairs along the edges and winged petioles. The tiny flowers are usually white, sometimes pink, and have notched petals 3 to 6 millimeters long. The fruit is a hairy capsule up to 10 centimeters in length. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 6 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 ~32 caterpillar species
Epilobium supports ~32 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 Epilobium in North America, including:
+ 8 more species → ↑ show fewer
Related plants
More Epilobium →
How we know this (3) Methods & honest limits
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 (18) 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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