When does Old Man's Beard Clematis bloom in Texas?

Most often in June. Across 338 dated, research-grade observations of Clematis drummondii in Texas, the flowering season runs roughly June to August.

Peak June In flower 338 Examined 511 State Texas

Flowering 338 in flower of 511 examined

30%

27%

63%

93%

92%

85%

59%

38%

23%

50%

Proportion of examined Clematis drummondii in Texas in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	3	10	30%	11% to 60%
Feb	1	16	6%	1% to 28%
Mar	1	11	9%	2% to 38%
Apr	7	26	27%	14% to 46%
May	25	40	63%	47% to 76%
Jun	86	92	93%	86% to 97%
Jul	86	93	92%	85% to 96%
Aug	61	72	85%	75% to 91%
Sep	39	66	59%	47% to 70%
Oct	20	53	38%	26% to 51%
Nov	6	26	23%	11% to 42%
Dec	3	6	50%	19% to 81%

Peak flowering in Jun. Each bar is the share of Clematis drummondii 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. 338 of 511 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 Texas found Clematis drummondii 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

Clematis drummondii

Old Man's Beard Clematis

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.