When does Johnson grass bloom in Texas?

Most often in July. Across 136 dated, research-grade observations of Sorghum halepense in Texas, the flowering season runs roughly April to July.

Peak July In flower 136 Examined 306 State Texas

Flowering 136 in flower of 306 examined

20%

18%

50%

57%

62%

63%

39%

43%

32%

28%

25%

Proportion of examined Sorghum halepense in Texas in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	1	5	20%	4% to 62%
Feb	0	3	too few examined
Mar	2	11	18%	5% to 48%
Apr	32	64	50%	38% to 62%
May	25	44	57%	42% to 70%
Jun	24	39	62%	46% to 75%
Jul	10	16	63%	39% to 82%
Aug	7	18	39%	20% to 61%
Sep	12	28	43%	27% to 61%
Oct	12	37	32%	20% to 49%
Nov	8	29	28%	15% to 46%
Dec	3	12	25%	9% to 53%

Peak flowering in Jul. Each bar is the share of Sorghum halepense 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. 136 of 306 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 Sorghum halepense 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

Sorghum halepense

Johnson grass

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.