When does birdwing passionflower bloom in Texas?

Most often in September. Across 159 dated, research-grade observations of Passiflora tenuiloba in Texas, the flowering season runs roughly September.

Peak September In flower 159 Examined 413 State Texas

Flowering 159 in flower of 413 examined

10%

50%

48%

38%

44%

64%

48%

11%

17%

Proportion of examined Passiflora tenuiloba in Texas in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	1	10	10%	2% to 40%
Feb	0	2	too few examined
Mar	3	45	7%	2% to 18%
Apr	42	84	50%	40% to 60%
May	22	44	50%	36% to 64%
Jun	14	29	48%	31% to 66%
Jul	8	21	38%	21% to 59%
Aug	8	18	44%	25% to 66%
Sep	29	45	64%	50% to 77%
Oct	23	48	48%	34% to 62%
Nov	5	44	11%	5% to 24%
Dec	4	23	17%	7% to 37%

Peak flowering in Sep. Each bar is the share of Passiflora tenuiloba 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. 159 of 413 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. One month has fewer than 5 examined observations, so no proportion is drawn for it. 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 Passiflora tenuiloba 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

Passiflora tenuiloba

birdwing passionflower

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.