When does Mountain Jewelflower bloom in California?

Most often in April. Across 303 dated, research-grade observations of Streptanthus tortuosus in California, the flowering season runs roughly March to August.

Peak April In flower 303 Examined 347 State California

Flowering 303 in flower of 347 examined

80%

94%

88%

90%

91%

77%

65%

Proportion of examined Streptanthus tortuosus in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	0	too few examined
Feb	1	1	too few examined
Mar	12	15	80%	55% to 93%
Apr	34	36	94%	82% to 98%
May	35	40	88%	74% to 95%
Jun	94	104	90%	83% to 95%
Jul	93	102	91%	84% to 95%
Aug	20	26	77%	58% to 89%
Sep	11	17	65%	41% to 83%
Oct	2	3	too few examined
Nov	1	3	too few examined
Dec	0	0	too few examined

Peak flowering in Apr. Each bar is the share of Streptanthus tortuosus 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. 303 of 347 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 5 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 Streptanthus tortuosus 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

Streptanthus tortuosus

Mountain Jewelflower

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.