When does Round-leaved Crane's-bill bloom in California?

Most often in April. Across 485 dated, research-grade observations of Geranium rotundifolium in California, the flowering season runs roughly March to November.

Peak April In flower 485 Examined 625 State California

Flowering 485 in flower of 625 examined

59%

68%

80%

90%

83%

66%

59%

44%

50%

47%

88%

65%

Proportion of examined Geranium rotundifolium in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	10	17	59%	36% to 78%
Feb	19	28	68%	49% to 82%
Mar	48	60	80%	68% to 88%
Apr	176	195	90%	85% to 94%
May	133	161	83%	76% to 88%
Jun	39	59	66%	53% to 77%
Jul	23	39	59%	43% to 73%
Aug	7	16	44%	23% to 67%
Sep	5	10	50%	24% to 76%
Oct	7	15	47%	25% to 70%
Nov	7	8	88%	53% to 98%
Dec	11	17	65%	41% to 83%

Peak flowering in Apr. Each bar is the share of Geranium rotundifolium 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. 485 of 625 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 Geranium rotundifolium 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

Geranium rotundifolium

Round-leaved Crane's-bill

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.