When does tree tobacco bloom in Arizona?

Most often in October. Across 151 dated, research-grade observations of Nicotiana glauca in Arizona, the flowering season runs roughly March to October.

Peak October In flower 151 Examined 230 State Arizona

Flowering 151 in flower of 230 examined

47%

14%

81%

77%

71%

67%

65%

60%

78%

86%

64%

57%

Proportion of examined Nicotiana glauca in Arizona in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	8	17	47%	26% to 69%
Feb	2	14	14%	4% to 40%
Mar	22	27	81%	63% to 92%
Apr	37	48	77%	63% to 87%
May	17	24	71%	51% to 85%
Jun	10	15	67%	42% to 85%
Jul	11	17	65%	41% to 83%
Aug	6	10	60%	31% to 83%
Sep	7	9	78%	45% to 94%
Oct	6	7	86%	49% to 97%
Nov	9	14	64%	39% to 84%
Dec	16	28	57%	39% to 73%

Peak flowering in Oct. Each bar is the share of Nicotiana glauca 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. 151 of 230 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 Nicotiana glauca 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

Nicotiana glauca

tree tobacco

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.