When does California goldenbush bloom in California?

Most often in September. Across 239 dated, research-grade observations of Ericameria ericoides in California, the flowering season runs roughly August to October.

Peak September In flower 239 Examined 361 State California

Flowering 239 in flower of 361 examined

Proportion of examined Ericameria ericoides in California in flower, by month
Month In flower Examined Share 95% interval
Jan 14 33 42% 27% to 59%
Feb 5 14 36% 16% to 61%
Mar 1 7 14% 3% to 51%
Apr 2 8 25% 7% to 59%
May 1 9 11% 2% to 44%
Jun 0 7 0% 0% to 35%
Jul 13 20 65% 43% to 82%
Aug 38 42 90% 78% to 96%
Sep 78 84 93% 85% to 97%
Oct 47 55 85% 74% to 92%
Nov 29 53 55% 41% to 67%
Dec 11 29 38% 23% to 56%

Peak flowering in Sep. Each bar is the share of Ericameria ericoides 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. 239 of 361 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 Ericameria ericoides 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

Sourcesevery claim on this page

  1. 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.
  2. World Flora Online Plant List. The accepted name. CC0. Retrieved 2026-07-12.