When does Silver Bush Lupine bloom in California?

Most often in May. Across 1,013 dated, research-grade observations of Lupinus albifrons in California, the flowering season runs roughly March to June.

Peak May In flower 1,013 Examined 1,168 State California

Flowering 1,013 in flower of 1,168 examined

49%

79%

95%

97%

99%

83%

38%

23%

19%

40%

Proportion of examined Lupinus albifrons in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	28	57	49%	37% to 62%
Feb	104	132	79%	71% to 85%
Mar	350	369	95%	92% to 97%
Apr	323	333	97%	95% to 98%
May	141	143	99%	95% to 100%
Jun	44	53	83%	71% to 91%
Jul	1	11	9%	2% to 38%
Aug	1	3	too few examined
Sep	5	13	38%	18% to 64%
Oct	3	13	23%	8% to 50%
Nov	3	16	19%	7% to 43%
Dec	10	25	40%	23% to 59%

Peak flowering in May. Each bar is the share of Lupinus albifrons 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. 1,013 of 1,168 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 Lupinus albifrons 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

Lupinus albifrons

Silver Bush Lupine

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.