When does swanflower bloom in Texas?

Most often in June. Across 386 dated, research-grade observations of Aristolochia erecta in Texas, the flowering season runs roughly April to October.

Peak June In flower 386 Examined 507 State Texas

Flowering 386 in flower of 507 examined

67%

25%

61%

86%

69%

90%

83%

70%

69%

81%

Proportion of examined Aristolochia erecta in Texas in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	4	6	67%	30% to 90%
Feb	2	8	25%	7% to 59%
Mar	30	49	61%	47% to 74%
Apr	86	100	86%	78% to 91%
May	37	54	69%	55% to 79%
Jun	66	73	90%	82% to 95%
Jul	59	71	83%	73% to 90%
Aug	48	69	70%	58% to 79%
Sep	35	51	69%	55% to 80%
Oct	17	21	81%	60% to 92%
Nov	0	3	too few examined
Dec	2	2	too few examined

Peak flowering in Jun. Each bar is the share of Aristolochia erecta in Texas 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. 386 of 507 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 Texas found Aristolochia erecta in flower, not a forecast. It is computed only from observations made in Texas, 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

Aristolochia erecta

swanflower

Sourcesevery claim on this page

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