When does Oregon fetid adderstongue bloom in Oregon?

Most often in March. Across 109 dated, research-grade observations of Scoliopus hallii in Oregon, the flowering season runs roughly March.

Peak March In flower 109 Examined 149 State Oregon

Flowering 109 in flower of 149 examined

89%

71%

33%

Proportion of examined Scoliopus hallii in Oregon in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	0	too few examined
Feb	3	4	too few examined
Mar	73	82	89%	80% to 94%
Apr	27	38	71%	55% to 83%
May	6	18	33%	16% to 56%
Jun	0	7	0%	0% to 35%
Jul	0	0	too few examined
Aug	0	0	too few examined
Sep	0	0	too few examined
Oct	0	0	too few examined
Nov	0	0	too few examined
Dec	0	0	too few examined

Peak flowering in Mar. Each bar is the share of Scoliopus hallii in Oregon observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 109 of 149 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 8 months have fewer than 5 examined observations, so no proportion is drawn for them. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.wt38fd.

What this is, and what it is not

This is a record of when people in Oregon found Scoliopus hallii in flower, not a forecast. It is computed only from observations made in Oregon, so it is not the species’ global average dragged onto a map: the same plant flowers on different dates in different places, and that is the entire point of the page.

It will not tell you what your particular plant will do this year. Bloom time moves with the season, with altitude, and with the weather, and a warm February pulls everything forward. We publish the distribution and the sample size, and we refuse to draw a month that too few people examined.

The plant

Scoliopus hallii

Oregon fetid adderstongue

Sourcesevery claim on this page

GBIF (iNaturalist Research-grade Observations). Dated flowering annotations in Oregon. Every record achieved iNaturalist quality grade Research, which is applied upstream at export. 10.15468/dl.wt38fd. Retrieved 2026-07-14.
World Flora Online Plant List. The accepted name. CC0. Retrieved 2026-07-12.