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Native Plant Society of Texas

Sawtooth Sunflower

Helianthus grosseserratus

Other common name(s):

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.

East Central Texas Plains, Western Gulf Coastal Plain
Bastrop Lost Pines, Floodplains and Low Terraces2, Northern Post Oak Savanna, Northern Prairie Outliers, San Antonio Prairie, Southern Post Oak Savanna
Flatwoods, Southern Tertiary Uplands

Plant Characteristics

Growth Form

Herbaceous

Height

3
to
15
ft.

Spread

3
to
6
ft.

Leaf Retention

Deciduous

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Caliche, Dry, Moist, Sand, Well Drained

Light Requirement

Sun

Water Requirement

Medium

Native Habitat

Grassland, Riparian, Woodland

Bloom and Attraction

Bloom Color

Yellow

Bloom Season

Summer, Fall

Seasonal Interest

Larval Host, Nectar, Pollen, Seeds

Wildlife Benefit

Bees, Birds, Butterflies, Moths, Small Mammals

Maintenance

In continuous rain or grown in a long time in partial shade, may grow poorly and become weak Tolerates wide temperature range. Prune in early to late spring, thin for airflow and sunlight. Deadhead to promote more flowering or leave seeds for wildlife. Will spread prolificially so give lots of space or thin according to garden space. Native habitat: dry to wet prairies, bottom lands, streams and in low woods.

Description

Blooms August – November. Reddish-purple stems erect, with coarsely serrated leaves, and pubescent underside. Small flower heads grow at the end of branched stems. ray flowers surrounding disc blowers. Larval host: Checkerspot.
Previous Scientific Name(s): Helianthus grosseserratus ssp. maximus, Helianthus grosseserratus var. hypoleucus, Helianthus instabilis

References

Learn about how to propagate Texas native plants.

Material Treatment Method Collection References
Seed Stratification Direct sow in late fall, planting the seeds 1/2" deep. For spring planting, mix the seed with moist sand and store it in the refrigerator for 30 days before direct sowing. To start indoors, sow seeds in a flat or individual peat pots, keeping the soil lightly moist and at a temperature of 65-70 degrees F until germination, which usually occurs within 10-20 days. Keep the seedlings moist. When the weather has warmed and the seedlings are well established, transplant outdoors. After their petals drop off, the centers of the flowers will darken and develop tight clusters of seed. Harvest the seed as soon as it ripens, since small birds love to eat it. Cut the heads and spread them out to dry for several days. Thresh the dried heads to separate the seed from the chaff. Store the cleaned seed in a cool, dry place. https://www.everwilde.com/store/Helianthus-grosseserratus-WildFlower-Seed.html
Seed Stratification The following steps for planting Sawtooth Sunflower seeds assume you are either Winter Sowing the seed, or have already cold-moist stratified (follow directions using the link provided in the References field. , Fill a suitable container with moist potting soil. Leave a 1/2″-3/4″ gap (6-9mm) from the top of the container. The potting soil should be wet enough that when you squeeze a handful only a few drops of water fall out. Gently tamp the soil firm Place 3-5 seeds on the soil surface. Press them so they have good contact. Cover seeds with 1/8″-1/4″ of moist potting soil. Place the container in a location that receives morning sun and afternoon shade. Keep the soil moist, watering as needed. Once germination occurs, grow the seedlings until they have 2-3 sets of true leaves. A couple other notes on caring for young seedlings. First, keeping the container in morning sun/afternoon shade is really beneficial. It allows the seedling sunlight for photosynthesis, but protects it from the hot afternoon sun, which can easily dry out small containers. https://growitbuildit.com/seed-stratification-illustrated-guide/

About the Region

2026 Fall Symposium Logo

This low-elevations region of Texas extends inland from the barrier islands, about 60 or so miles, and stretches from Brownsville to Louisiana. In total, it covers about 9.5 million acres, with a high point of 150 feet in elevation. More than 1000 species of plants can be found in this region. On the southern end, species more common in Mexico (such as Sabal mexicana) and Central America occur.

The barrier islands provide us with dune systems, and clay flats to the inland side, which have species found in these areas alone. Many plants here, such as Ipomoea pes-caprae (beach morning glory), can be found throughout tropical regions of the globe. I’ve encountered the same species on the beaches of Guam.

Once inland, vast marshes and wet prairies occur. Occasionally, oak (Quercus fusiformis) groves can be found. Common grasses include species of Bothriochloa, Paspalum, and Sporobolus; eastern gamagrass (Tripsacum dactyloides); and switchgrass (Panicum species). Many rivers and creeks cut through the Gulf Prairies, and along these riparian areas various species of trees, Sabal minor, and other plants adapted to clay soils can be found. Due to overgrazing, farming, and fire suppression, woody species such as mesquite (Prosopis glandulosa) and huisache (Acacia farnesiana), and invasive species such as chinaberry (Melia azedarach), Brazilian pepper (Schinus terebinthifolius), and Chinese tallow (Sapium sebiferum) have increased and displaced our native flora.

Source: Wildflowers of Texas by Michael Eason