When does coastal buckwheat bloom in California?

Most often in July. Across 127 dated, research-grade observations of Eriogonum cinereum in California, the flowering season runs roughly January to November.

Peak July In flower 127 Examined 165 State California

Flowering 127 in flower of 165 examined

77%

63%

33%

83%

86%

96%

93%

94%

87%

71%

Proportion of examined Eriogonum cinereum in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	10	13	77%	50% to 92%
Feb	5	8	63%	31% to 86%
Mar	4	12	33%	14% to 61%
Apr	5	15	33%	15% to 58%
May	10	12	83%	55% to 95%
Jun	6	7	86%	49% to 97%
Jul	24	25	96%	80% to 99%
Aug	14	15	93%	70% to 99%
Sep	17	18	94%	74% to 99%
Oct	4	4	too few examined
Nov	13	15	87%	62% to 96%
Dec	15	21	71%	50% to 86%

Peak flowering in Jul. Each bar is the share of Eriogonum cinereum in California 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. 127 of 165 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. 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 California found Eriogonum cinereum in flower, not a forecast. It is computed only from observations made in California, 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

Eriogonum cinereum

coastal buckwheat

Sourcesevery claim on this page

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