When does queen's-root bloom in California?

Most often in April. Across 172 dated, research-grade observations of Stillingia linearifolia in California, the flowering season runs roughly March to November.

Peak April In flower 172 Examined 241 State California

Flowering 172 in flower of 241 examined

50%

65%

83%

76%

73%

77%

50%

Proportion of examined Stillingia linearifolia in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	10	20	50%	30% to 70%
Feb	26	40	65%	50% to 78%
Mar	43	52	83%	70% to 91%
Apr	44	53	83%	71% to 91%
May	16	21	76%	55% to 89%
Jun	1	1	too few examined
Jul	0	0	too few examined
Aug	0	2	too few examined
Sep	0	2	too few examined
Oct	11	15	73%	48% to 89%
Nov	10	13	77%	50% to 92%
Dec	11	22	50%	31% to 69%

Peak flowering in Apr. Each bar is the share of Stillingia linearifolia 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. 172 of 241 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 4 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 California found Stillingia linearifolia 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

Stillingia linearifolia

queen's-root

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.