When does Erythranthe grandis bloom in California?

Most often in July. Across 516 dated, research-grade observations of Erythranthe grandis in California, the flowering season runs roughly April to November.

Peak July In flower 516 Examined 539 State California

Flowering 516 in flower of 539 examined

Proportion of examined Erythranthe grandis in California in flower, by month
Month In flower Examined Share 95% interval
Jan 6 8 75% 41% to 93%
Feb 7 11 64% 35% to 85%
Mar 16 22 73% 52% to 87%
Apr 48 51 94% 84% to 98%
May 56 57 98% 91% to 100%
Jun 135 137 99% 95% to 100%
Jul 96 96 100% 96% to 100%
Aug 67 69 97% 90% to 99%
Sep 44 44 100% 92% to 100%
Oct 29 30 97% 83% to 99%
Nov 11 13 85% 58% to 96%
Dec 1 1 too few examined

Peak flowering in Jul. Each bar is the share of Erythranthe grandis 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. 516 of 539 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. 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 Erythranthe grandis 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.