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Native Plant Society of Texas

Inland Sea Oats

Chasmanthium latifolium

Other common name(s):

Indian Wood Oats, Wild Oats, River Oats, Flathead Oats, Upland Oats, Upland Sea Oats, Broadleaf Wood Oats

Family:

Poaceae (Grass 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.

Cross Timbers, East Central Texas Plains, Edwards Plateau, Gulf Coast Prairies and Marshes, Southern Texas Plains, Texas Blackland Prairies, Western Gulf Coastal Plain
Carbonate Cross Timbers, Eastern Cross Timbers, Grand Prairie, Limestone Cut Plain, Western Cross Timbers
Bastrop Lost Pines, Floodplains and Low Terraces2, Northern Post Oak Savanna, Northern Prairie Outliers, San Antonio Prairie, Southern Post Oak Savanna
Balcones Canyonlands, Edwards Plateau Woodland, Llano Uplift
Floodplains and Low Terraces4, Lower Rio Grande Valley, Northern Humid Gulf Coastal Prairies, Southern Subhumid Gulf Coastal Prairies, Texas-Louisiana Coastal Marshes
Northern Nueces Alluvial Plains
Floodplains and Low Terraces1, Northern Blackland Prairie, Southern Blackland Prairie
Flatwoods, Floodplains and Low Terraces3, Pleistocene Fluvial Terraces, Red River Bottomlands, Southern Tertiary Uplands, Tertiary Uplands

Plant Characteristics

Growth Form

Grass & Sedge

Height

2
to
4
ft.

Spread

2
to
3
ft.

Leaf Retention

Deciduous

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Calcareous, Clay, Limestone, Loam, Moist, Poor Drainage, Sand

Light Requirement

Part Shade, Shade

Water Requirement

Low, Medium

Native Habitat

Riparian, Woodland

Bloom and Attraction

Bloom Color

Green

Bloom Season

Summer, Fall

Seasonal Interest

Forage, Larval Host, Seeds

Wildlife Benefit

Birds, Butterflies, Small Mammals

Maintenance

Very popular as a low-maintenance shade grass. Leave dry stalks for wildlife during the winter. Cut back dead stalks in the spring before new shoots emerge. Reseeds easily and spreads by rhizomes, so give lots of room or pull sprouts to control according to garden space. Can be used to prevent soil erosion along streams. The seed stalks are attractive in flower arrangements. Native habitat: shaded slopes, low thickets, stream banks, shaded floodplains, moist woods, clay soils of bottomlands, upland woods and even on the rocky cliffs,

Description

Blooms June-September. A warm-season, clump-forming, grass. Produces characteristic large, drooping, oat-like flower spikelets. Seed heads and leaves turn golden in the fall. Seeds are eaten by birds and rodents. Foliage provides cover for small mammals. Larval host: Pepper and Salt Skipper, Bell’s Roadside Skipper, and Bronze Roadside Skipper. Replaces non-native: Maiden Grass, Chinese Silvergrass.
Previous Scientific Name(s): Uniola latifolia

References

Learn about how to propagate Texas native plants.

Material Treatment Method Collection References
Seed No Treatment Indoors: Plant seed 0.64 cm (1/4 inch) deep in pots. Keep moist but not soggy and very warm (21 C - 70 F). When seedlings are 5 cm (2 in.) tall, transplant into the garden spaced 30 cm (1 ft.) apart. Outdoors: Sow seed 0.64 cm (1/4 inch) deep outdoors in either late fall or early spring. Collect seed in fall. https://wwhttps://www.wildflowerfarm.com/chasmanthium-latifolium-northern-sea-oats.html#:~:text=Plant%20seed%200.64%20cm%20(1,30%20cm%20(1%20ft.)
Seed Scarification Best germination can be achieved with a short period of cold, moist stratification. Sow outdoors by March or stratify with moist sand/potting soil in the refrigerator for 2 to 4 weeks. https://mowildflowers.net/chasmanthium-latifolium--river-oats-/#:~:text=Seed:%20Best%20germination%20can%20be,for%202%20to%204%20weeks.
Clump Division Moisten soil. Gently remove clumps. Tease apart roots and divide into smaller clumps. Replant in new location immediately. Kee moist but not soggy until they appear to be well established. Best to do in the spring while it is cool to put less stress on plants and allow roots to develop before dormancy in the winter. Claire Sorenson, NPSOT member observation.

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