When does common woolly sunflower bloom in Washington?

Most often in June. Across 174 dated, research-grade observations of Eriophyllum lanatum in Washington, the flowering season runs roughly May to August.

Peak June In flower 174 Examined 309 State Washington

Flowering 174 in flower of 309 examined

18%

69%

77%

72%

63%

40%

Proportion of examined Eriophyllum lanatum in Washington in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	5	0%	0% to 43%
Feb	0	2	too few examined
Mar	0	12	0%	0% to 24%
Apr	7	38	18%	9% to 33%
May	44	64	69%	57% to 79%
Jun	65	84	77%	67% to 85%
Jul	26	36	72%	56% to 84%
Aug	24	38	63%	47% to 77%
Sep	8	20	40%	22% to 61%
Oct	0	9	0%	0% to 30%
Nov	0	1	too few examined
Dec	0	0	too few examined

Peak flowering in Jun. Each bar is the share of Eriophyllum lanatum in Washington 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. 174 of 309 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 3 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 Washington found Eriophyllum lanatum in flower, not a forecast. It is computed only from observations made in Washington, 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

Eriophyllum lanatum

common woolly sunflower

Sourcesevery claim on this page

GBIF (iNaturalist Research-grade Observations). Dated flowering annotations in Washington. 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.