When does wild canterbury bells bloom in California?

Most often in July. Across 1,713 dated, research-grade observations of Phacelia minor in California, the flowering season runs roughly January to November.

Peak July In flower 1,713 Examined 1,751 State California

Flowering 1,713 in flower of 1,751 examined

Proportion of examined Phacelia minor in California in flower, by month
Month In flower Examined Share 95% interval
Jan 119 128 93% 87% to 96%
Feb 266 275 97% 94% to 98%
Mar 611 618 99% 98% to 99%
Apr 420 423 99% 98% to 100%
May 201 204 99% 96% to 100%
Jun 56 59 95% 86% to 98%
Jul 11 11 100% 74% to 100%
Aug 3 3 too few examined
Sep 0 0 too few examined
Oct 6 7 86% 49% to 97%
Nov 9 9 100% 70% to 100%
Dec 11 14 79% 52% to 92%

Peak flowering in Jul. Each bar is the share of Phacelia minor 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. 1,713 of 1,751 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 2 months have fewer than 5 examined observations, so no proportion is drawn for them. 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 Phacelia minor 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.