When does mule fat bloom in California?

Most often in March. Across 754 dated, research-grade observations of Baccharis salicifolia in California, the flowering season runs roughly January to November.

Peak March In flower 754 Examined 1,008 State California

Flowering 754 in flower of 1,008 examined

74%

72%

84%

81%

71%

55%

70%

55%

56%

72%

82%

66%

Proportion of examined Baccharis salicifolia in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	93	125	74%	66% to 81%
Feb	98	137	72%	63% to 78%
Mar	179	214	84%	78% to 88%
Apr	130	161	81%	74% to 86%
May	37	52	71%	58% to 82%
Jun	16	29	55%	38% to 72%
Jul	14	20	70%	48% to 85%
Aug	11	20	55%	34% to 74%
Sep	22	39	56%	41% to 71%
Oct	44	61	72%	60% to 82%
Nov	58	71	82%	71% to 89%
Dec	52	79	66%	55% to 75%

Peak flowering in Mar. Each bar is the share of Baccharis salicifolia 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. 754 of 1,008 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 Baccharis salicifolia 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

Baccharis salicifolia

mule fat

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.