When does cheeseweed mallow bloom in California?

Most often in March. Across 1,511 dated, research-grade observations of Malva parviflora in California, the flowering season runs roughly February to September.

Peak March In flower 1,511 Examined 2,924 State California

Flowering 1,511 in flower of 2,924 examined

44%

47%

58%

55%

51%

50%

49%

42%

54%

46%

21%

23%

Proportion of examined Malva parviflora in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	42	95	44%	35% to 54%
Feb	97	206	47%	40% to 54%
Mar	282	486	58%	54% to 62%
Apr	617	1126	55%	52% to 58%
May	266	524	51%	46% to 55%
Jun	78	156	50%	42% to 58%
Jul	39	79	49%	39% to 60%
Aug	15	36	42%	27% to 58%
Sep	29	54	54%	41% to 66%
Oct	19	41	46%	32% to 61%
Nov	13	61	21%	13% to 33%
Dec	14	60	23%	14% to 35%

Peak flowering in Mar. Each bar is the share of Malva parviflora 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. 1,511 of 2,924 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 parviflora 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 parviflora

cheeseweed 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.