When does tropical milkweed bloom in Florida?

Most often in September. Across 324 dated, research-grade observations of Asclepias curassavica in Florida, the flowering season runs roughly January to December.

Peak September In flower 324 Examined 352 State Florida

Flowering 324 in flower of 352 examined

90%

96%

91%

87%

97%

93%

89%

86%

100%

94%

90%

97%

Proportion of examined Asclepias curassavica in Florida in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	52	58	90%	79% to 95%
Feb	27	28	96%	82% to 99%
Mar	63	69	91%	82% to 96%
Apr	41	47	87%	75% to 94%
May	28	29	97%	83% to 99%
Jun	14	15	93%	70% to 99%
Jul	8	9	89%	56% to 98%
Aug	6	7	86%	49% to 97%
Sep	6	6	100%	61% to 100%
Oct	15	16	94%	72% to 99%
Nov	26	29	90%	74% to 96%
Dec	38	39	97%	87% to 100%

Peak flowering in Sep. Each bar is the share of Asclepias curassavica 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. 324 of 352 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 Florida found Asclepias curassavica 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

Asclepias curassavica

tropical milkweed

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.