When does sessileflower false goldenaster bloom in California?

Most often in January. Across 315 dated, research-grade observations of Heterotheca sessiliflora in California, the flowering season runs roughly January to December.

Peak January In flower 315 Examined 380 State California

Flowering 315 in flower of 380 examined

100%

67%

30%

47%

32%

61%

96%

81%

82%

Proportion of examined Heterotheca sessiliflora in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	7	7	100%	65% to 100%
Feb	4	6	67%	30% to 90%
Mar	3	10	30%	11% to 60%
Apr	7	15	47%	25% to 70%
May	7	22	32%	16% to 53%
Jun	17	28	61%	42% to 76%
Jul	47	49	96%	86% to 99%
Aug	52	54	96%	87% to 99%
Sep	68	71	96%	88% to 99%
Oct	46	48	96%	86% to 99%
Nov	34	42	81%	67% to 90%
Dec	23	28	82%	64% to 92%

Peak flowering in Jan. Each bar is the share of Heterotheca sessiliflora 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. 315 of 380 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 Heterotheca sessiliflora 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

Heterotheca sessiliflora

sessileflower false goldenaster

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.