When does two-color rabbit-tobacco bloom in California?

Most often in March. Across 211 dated, research-grade observations of Pseudognaphalium biolettii in California, the flowering season runs roughly March.

Peak March In flower 211 Examined 357 State California

Flowering 211 in flower of 357 examined

Proportion of examined Pseudognaphalium biolettii in California in flower, by month
Month In flower Examined Share 95% interval
Jan 17 38 45% 30% to 60%
Feb 44 68 65% 53% to 75%
Mar 60 71 85% 74% to 91%
Apr 50 76 66% 55% to 75%
May 14 24 58% 39% to 76%
Jun 3 9 33% 12% to 65%
Jul 2 6 33% 10% to 70%
Aug 3 7 43% 16% to 75%
Sep 1 6 17% 3% to 56%
Oct 2 12 17% 5% to 45%
Nov 0 13 0% 0% to 23%
Dec 15 27 56% 37% to 72%

Peak flowering in Mar. Each bar is the share of Pseudognaphalium biolettii 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. 211 of 357 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 Pseudognaphalium biolettii 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.