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Trending: eastern poison ivy (Toxicodendron radicans) — 923 observations this week

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Phenology

Poison ivy is hitting peak urushiol potency right now — the same week crowds are heading onto trails — and being able to recognize its shiny three-leaflet clusters before you grab a trailside branch could save you a miserable two-week rash.

Poison ivy is one of the most-spotted plants on iNaturalist this week, with nearly a thousand confirmed sightings. Spring is when it's easiest to encounter because the plant is leafing out right as people head outdoors. Knowing what it looks like — three shiny leaves, sometimes with a reddish tinge when young — is genuinely useful safety knowledge for anyone spending time outside.

Key Findings

1

923 research-grade observations recorded in a single week, ranking eastern poison ivy among the top observed plant species nationally

2

Observation spike aligns with late-spring leaf-out period when urushiol-containing leaves are newly emerged and contact risk is elevated

3

Citizen-science data captures real-time geographic distribution, helping track range shifts and density in suburban and urban-edge habitats

chevron_right Technical Summary

Eastern poison ivy is surging in iNaturalist observations this week, with 923 research-grade sightings logged across its range. This spike likely reflects peak seasonal activity as the plant leafs out and hikers venture into woods and trails.

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eastern poison ivy is among the most observed plant species this week with 923 research-grade observations.

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hub This connects to 11 other discoveries — Eastern Poison Ivy phenology, urban-ecology, native-plants +2 more 5 related articles

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Toxicodendron radicans

Toxicodendron radicans, commonly known as eastern poison ivy or poison ivy, is a species of allergenic flowering plant. It has numerous subtaxons and forms both vines and shrubs. Despite its common name, it is not a true ivy, but rather a member of the cashew and sumac family, Anacardiaceae. It i...