When does bull mallow bloom in California?

Most often in January. Across 840 dated, research-grade observations of Malva nicaeensis in California, the flowering season runs roughly January to December.

Peak January In flower 840 Examined 919 State California

Flowering 840 in flower of 919 examined

100%

95%

93%

91%

90%

92%

80%

50%

83%

95%

Proportion of examined Malva nicaeensis in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	25	25	100%	87% to 100%
Feb	42	44	95%	85% to 99%
Mar	53	56	95%	85% to 98%
Apr	213	229	93%	89% to 96%
May	225	248	91%	86% to 94%
Jun	116	129	90%	84% to 94%
Jul	66	73	90%	82% to 95%
Aug	49	53	92%	82% to 97%
Sep	24	30	80%	63% to 91%
Oct	3	6	50%	19% to 81%
Nov	5	6	83%	44% to 97%
Dec	19	20	95%	76% to 99%

Peak flowering in Jan. Each bar is the share of Malva nicaeensis 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. 840 of 919 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 Malva nicaeensis 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

Malva nicaeensis

bull mallow

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.