When does lacy tansyaster bloom in Texas?

Most often in July. Across 137 dated, research-grade observations of Xanthisma spinulosum in Texas, the flowering season runs roughly March to October.

Peak July In flower 137 Examined 148 State Texas

Flowering 137 in flower of 148 examined

86%

97%

95%

90%

100%

89%

100%

Proportion of examined Xanthisma spinulosum in Texas in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	1	4	too few examined
Feb	2	3	too few examined
Mar	12	14	86%	60% to 96%
Apr	34	35	97%	85% to 99%
May	21	22	95%	78% to 99%
Jun	19	21	90%	71% to 97%
Jul	11	11	100%	74% to 100%
Aug	8	9	89%	56% to 98%
Sep	14	14	100%	78% to 100%
Oct	14	14	100%	78% to 100%
Nov	1	1	too few examined
Dec	0	0	too few examined

Peak flowering in Jul. Each bar is the share of Xanthisma spinulosum 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. 137 of 148 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 Xanthisma spinulosum 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

Xanthisma spinulosum

lacy tansyaster

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.