When does Trailing Windmills bloom in Arizona?

Most often in January. Across 237 dated, research-grade observations of Allionia incarnata in Arizona, the flowering season runs roughly January to December.

Peak January In flower 237 Examined 245 State Arizona

Flowering 237 in flower of 245 examined

Proportion of examined Allionia incarnata in Arizona in flower, by month
Month In flower Examined Share 95% interval
Jan 5 5 100% 57% to 100%
Feb 2 2 too few examined
Mar 13 14 93% 69% to 99%
Apr 52 52 100% 93% to 100%
May 35 36 97% 86% to 100%
Jun 3 4 too few examined
Jul 9 10 90% 60% to 98%
Aug 21 21 100% 85% to 100%
Sep 22 26 85% 66% to 94%
Oct 35 35 100% 90% to 100%
Nov 27 27 100% 88% to 100%
Dec 13 13 100% 77% to 100%

Peak flowering in Jan. Each bar is the share of Allionia incarnata in Arizona 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. 237 of 245 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 2 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 Arizona found Allionia incarnata in flower, not a forecast. It is computed only from observations made in Arizona, 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 Arizona. 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.