When does Creosote Bush bloom in Arizona?

Most often in April. Across 475 dated, research-grade observations of Larrea tridentata in Arizona, the flowering season runs roughly March to April.

Peak April In flower 475 Examined 891 State Arizona

Flowering 475 in flower of 891 examined

49%

50%

75%

76%

48%

22%

38%

35%

39%

42%

37%

Proportion of examined Larrea tridentata in Arizona in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	46	94	49%	39% to 59%
Feb	38	76	50%	39% to 61%
Mar	121	161	75%	68% to 81%
Apr	120	158	76%	69% to 82%
May	31	65	48%	36% to 60%
Jun	9	41	22%	12% to 37%
Jul	5	23	22%	10% to 42%
Aug	21	55	38%	27% to 51%
Sep	13	37	35%	22% to 51%
Oct	13	33	39%	25% to 56%
Nov	25	59	42%	31% to 55%
Dec	33	89	37%	28% to 47%

Peak flowering in Apr. Each bar is the share of Larrea tridentata 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. 475 of 891 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 Arizona found Larrea tridentata 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

Larrea tridentata

Creosote Bush

Sourcesevery claim on this page

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.
World Flora Online Plant List. The accepted name. CC0. Retrieved 2026-07-12.