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Native Plant Society of Texas

Mexican Trixis

Trixis inula

Other common name(s):

Hierba del Aire, Tropical Threefold

Family:

Asteraceae (Aster Family)

Plant Ecoregion Distribution Map

This map uses data from the US EPA. EPA  servers have been offline frequently so maps may not display. We are working on a solution.

Gulf Coast Prairies and Marshes
Lower Rio Grande Alluvial Floodplain, Lower Rio Grande Valley

Plant Characteristics

Growth Form

Shrub

Height

2
to
6
ft.

Spread

2
to
6
ft.

Leaf Retention

Semi Evergreen

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Sand, Loam, Clay, Dry

Light Requirement

Sun, Part Shade

Water Requirement

Low

Native Habitat

Grassland

Bloom and Attraction

Bloom Color

Yellow

Bloom Season

Spring, Summer, Fall

Seasonal Interest

Nectar

Wildlife Benefit

Butterflies

Maintenance

Will go dormant in extreme heat. Tends to flower after rains. A grouping of two or three, three feet apart will fill in a garden with color. Planted singly, it can spread to four feet or more. The blooms will attract countless butterflies. Native habitat: open, sandy sites, thorn scrub, palm groves, thickets. Propagation: seed, semi-hardwood cutting.

Comments

Blooms March-November. A much branched, sprawling shrub with lance shaped leaves. Flowers are clustered in branched panicles at the end of stems. In the Rio Grande Valley, four plant species of the Aster family share this two-lipped flower characteristic; Trixis is the only one with yellow flowers. The fruit is a cypsela: a dry, one-seeded fruit, usually topped by pappus.
Previous Scientific Name(s): Trixis radialis

References

1) https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=38581&print_version=SCR&source=from_print#null, 2) https://bonap.net/TDC/Image/Map?taxonType=Species&taxonId=4715&locationType=County&mapType=Normal, 3) https://www.wildflower.org/plants/result.php?id_plant=TRIN6, 4) https://portal.torcherbaria.org/portal/taxa/index.php?taxon=Trixis+inula&formsubmit=Search+Terms, 5) Richardson, Alfred. Plants of Deep South Texas: A Field Guide to the Woody and Flowering Species (Perspectives on South Texas, sponsored by Texas A&M University-Kingsville), p. 133. Texas A&M University Press, 6) https://nativeplantproject.com/Shrubs/trixis.htm, 6) https://en.wikipedia.org/wiki/Trixis_inula#:~:text=Trixis%20inula%20is%20a%20much,are%20borne%20in%20paniculate%20arrays., 7) https://rgvctmn.org/blog/prepare-for-the-butterfly-season/,

Learn about how to propagate Texas native plants.

Material Treatment Method Collection References
Seed No Treatment Begin sowing indoors 6-8 weeks before the last frost. This provides a head start, ensuring robust seedlings for transplanting when the weather warms up. Use a well-draining seed starting mix. Sow seeds evenly and thinly, covering them lightly with soil. Maintain a warm environment (around 70-75°F). Mist the soil regularly to keep it consistently moist but not waterlogged. Once seedlings emerge (typically in 1-2 weeks), provide ample sunlight or grow lights to promote strong growth. Harden off the seedlings gradually before transplanting them outdoors after the last frost, spacing them about 12-18 inches apart. https://propagate.one/how-to-propagate-trixis-inula/?amp=1&print=pdf
Clump division Division Gently dig up a mature clump and use a sharp knife or garden spade to divide it into smaller sections. Ensure each division has a good portion of roots and foliage. Replant the divisions at the same depth they were originally growing. Water thoroughly to help them establish in their new home. Early spring or fall, when the weather is cooler, is the ideal time for dividing Trixis Inula. https://propagate.one/how-to-propagate-trixis-inula/?amp=1&print=pdf
Stem Cutting Using clean, sharp shears, cut a 4-6 inch section from the tip of the stem, just below a leaf node. Remove the lower leaves from the cutting. While optional, dipping the cut end in rooting hormone powder can increase success rates. Insert the cuttings into a well-draining potting mix. Cover the pot with a plastic bag to maintain humidity. Keep the cuttings in a bright, indirect light location. In a few weeks, gently tug on the cutting – resistance means roots have formed! Select healthy, non-flowering stems from a vigorous Trixis Inula plant. https://propagate.one/how-to-propagate-trixis-inula/?amp=1&print=pdf

About the Region

Fall Symposium 2025 Logo - Teach for the Future

Salado, the location of our Fall 2025 Symposium, lies at the intersection of two ecoregions: the Edwards Plateau (Limestone Cut Plain) and Blackland Prairie (Northern Blackland Prairie).

The Edwards Plateau area is also called the Hill Country; however, this general term covers a much larger area extending farther north. Spring-fed creeks are found throughout the region; deep limestone canyons, rivers, and lakes (reservoirs) are common. Ashe juniper is perhaps the most common woody species found throughout the region. Additional woody species include various species of oak, with live oak (Quercus fusiformis) being the most common. Sycamores (Platanus occidentalis) and bald cypress (Taxodium distichum) border waterways. This area is well known for its spring wildflower displays, though they may be viewed in spring, late summer, and fall, as well. According to Texas Parks and Wildlife, average annual rainfall in the Edwards Plateau ranges from 15 to 34 inches.

The Blackland Prairie extends from the Red River south to San Antonio, bordered on the west by the Edwards Plateau and the Cross Timbers, and on the east by the Post Oak Savannah. Annual rainfall averages 30 to 40 inches, with higher averages to the east. This region is dominated by prairie species. The most common grass species include little bluestem (Schizachyrium scoparium) and Indian grass (Sorghastrum nutans) in the uplands and switchgrass (Panicum virgatum) in the riparian areas and drainages. Common herbaceous flowering plants include salvias, penstemons, and silphiums. This area has suffered greatly from overgrazing and agricultural use. Few intact areas remain, though many of the plants can be found along county roadsides throughout the region.

Our fall Symposium host chapter, the Tonkawa Chapter, includes both of these ecoregions.

Source: Wildflowers of Texas by Michael Eason