Swamp Sunflower

Helianthus angustifolius

Other common name(s):

Narrowleaf Sunflower, Narrow-leaved Sunflower

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, Western Gulf Coastal Plain
Lower Rio Grande Valley, Northern Humid Gulf Coastal Prairies
Flatwoods, Floodplains and Low Terraces3, Pleistocene Fluvial Terraces, Red River Bottomlands, Southern Tertiary Uplands, Tertiary Uplands

Plant Characteristics

Growth Form

Herbaceous

Height

3
to
6
ft.

Spread

0.5
to
1
ft.

Leaf Retention

Deciduous

Lifespan

Perennial

Habitat and Care Requirements

Soil Type(s)

Sand, Loam, Clay, Moist

Light Requirement

Sun, Part Shade

Water Requirement

High

Native Habitat

Wetland or Riparian

Bloom and Attraction

Bloom Color

Yellow

Bloom Season

Fall

Seasonal Interest

Seeds, Nectar, Pollen, Larval Host

Wildlife Benefit

Butterflies, Birds

Maintenance

Low maintenance. Good plant for the back of boggy and marshy gardens. Spreads by rhizomes and can get leggy. Stems can be pinched back in late spring or early summer to encourage shorter, bushier growth and more blooms. Propagation: seed, root division.

Comments

Blooms August-November. A tall, showy, short-lived perennial. Leaves are long and have a rough, sandpaper-like surface. The flower heads are large, up to 3-in. The golden yellow outer florets surround a compact head of reddish-brown disk florets. Flower heads are cupped in green, hairy bracts. The fruit is a cypsela: a dry, one-seeded fruit, usually topped by pappus. Larval host: Bordered Patch.
Previous Scientific Name(s): Helianthus angustifolius var. planifolius

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