When does Wild radish bloom in California?

Most often in January. Across 1,084 dated, research-grade observations of Raphanus raphanistrum in California, the flowering season runs roughly January to December.

Peak January In flower 1,084 Examined 1,127 State California

Flowering 1,084 in flower of 1,127 examined

100%

94%

97%

98%

92%

93%

91%

93%

100%

93%

97%

Proportion of examined Raphanus raphanistrum in California in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	45	45	100%	92% to 100%
Feb	61	65	94%	85% to 98%
Mar	158	163	97%	93% to 99%
Apr	330	337	98%	96% to 99%
May	167	170	98%	95% to 99%
Jun	100	109	92%	85% to 96%
Jul	83	89	93%	86% to 97%
Aug	39	43	91%	78% to 96%
Sep	42	45	93%	82% to 98%
Oct	15	15	100%	80% to 100%
Nov	13	14	93%	69% to 99%
Dec	31	32	97%	84% to 99%

Peak flowering in Jan. Each bar is the share of Raphanus raphanistrum 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. 1,084 of 1,127 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 Raphanus raphanistrum 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

Raphanus raphanistrum

Wild radish

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.