When does American water-willow bloom in Texas?

Most often in June. Across 326 dated, research-grade observations of Dianthera americana in Texas, the flowering season runs roughly April to October.

Peak June In flower 326 Examined 360 State Texas

Flowering 326 in flower of 360 examined

29%

94%

95%

98%

96%

75%

96%

85%

Proportion of examined Dianthera americana in Texas in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	0	0	too few examined
Feb	0	1	too few examined
Mar	4	14	29%	12% to 55%
Apr	91	97	94%	87% to 97%
May	78	82	95%	88% to 98%
Jun	49	50	98%	90% to 100%
Jul	24	25	96%	80% to 99%
Aug	15	20	75%	53% to 89%
Sep	52	54	96%	87% to 99%
Oct	11	13	85%	58% to 96%
Nov	2	4	too few examined
Dec	0	0	too few examined

Peak flowering in Jun. Each bar is the share of Dianthera americana 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. 326 of 360 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. 4 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 Dianthera americana 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

Dianthera americana

American water-willow

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.