When does buttonbush bloom in Florida?

Most often in March. Across 238 dated, research-grade observations of Cephalanthus occidentalis in Florida, the flowering season runs roughly March to August.

Peak March In flower 238 Examined 426 State Florida

Flowering 238 in flower of 426 examined

71%

57%

69%

68%

62%

41%

13%

14%

Proportion of examined Cephalanthus occidentalis in Florida in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	6	0%	0% to 39%
Feb	1	1	too few examined
Mar	5	7	71%	36% to 92%
Apr	35	61	57%	45% to 69%
May	83	121	69%	60% to 76%
Jun	45	66	68%	56% to 78%
Jul	26	42	62%	47% to 75%
Aug	23	37	62%	46% to 76%
Sep	12	29	41%	26% to 59%
Oct	5	38	13%	6% to 27%
Nov	2	14	14%	4% to 40%
Dec	1	4	too few examined

Peak flowering in Mar. Each bar is the share of Cephalanthus occidentalis in Florida 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. 238 of 426 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 Florida found Cephalanthus occidentalis in flower, not a forecast. It is computed only from observations made in Florida, 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

Cephalanthus occidentalis

buttonbush

Sourcesevery claim on this page

GBIF (iNaturalist Research-grade Observations). Dated flowering annotations in Florida. 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.