When does scarlet pimpernel bloom in California?

Most often in March. Across 2,954 dated, research-grade observations of Lysimachia arvensis in California, the flowering season runs roughly March to June.

Peak March In flower 2,954 Examined 5,038 State California

Flowering 2,954 in flower of 5,038 examined

20%

53%

67%

62%

60%

64%

50%

41%

29%

43%

17%

Proportion of examined Lysimachia arvensis in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	20	102	20%	13% to 28%
Feb	117	220	53%	47% to 60%
Mar	551	828	67%	63% to 70%
Apr	1238	2010	62%	59% to 64%
May	540	906	60%	56% to 63%
Jun	232	363	64%	59% to 69%
Jul	80	159	50%	43% to 58%
Aug	63	125	50%	42% to 59%
Sep	51	123	41%	33% to 50%
Oct	24	82	29%	21% to 40%
Nov	29	68	43%	32% to 54%
Dec	9	52	17%	9% to 30%

Peak flowering in Mar. Each bar is the share of Lysimachia arvensis 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. 2,954 of 5,038 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 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 Lysimachia arvensis 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

Lysimachia arvensis

scarlet pimpernel

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.