When does sticky sandspurry bloom in California?

Most often in March. Across 86 dated, research-grade observations of Spergularia macrotheca in California, the flowering season runs roughly March to October.

Peak March In flower 86 Examined 93 State California

Flowering 86 in flower of 93 examined

Proportion of examined Spergularia macrotheca in California in flower, by month
Month In flower Examined Share 95% interval
Jan 2 3 too few examined
Feb 0 0 too few examined
Mar 9 9 100% 70% to 100%
Apr 10 11 91% 62% to 98%
May 7 7 100% 65% to 100%
Jun 27 28 96% 82% to 99%
Jul 10 12 83% 55% to 95%
Aug 6 7 86% 49% to 97%
Sep 6 7 86% 49% to 97%
Oct 5 5 100% 57% to 100%
Nov 3 3 too few examined
Dec 1 1 too few examined

Peak flowering in Mar. Each bar is the share of Spergularia macrotheca 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. 86 of 93 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 4 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 Spergularia macrotheca 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.