Helianthus angustifolius

swamp sunflower, swamp sneezeweed, narrowleaf sunflower, narrow-leaved sunflower
Family

Asteraceae

Leaf Arrangement

alternate

Leaf Attachment

petiolate

Leaf Type

simple

Leaf Shape

linear

Growth Form

forb

Flower Color

yellow

Flower Petals

many

Flower Month

July - November

Height (meters)

0.9 - 2.0

Milky Sap

No

Armed/Unarmed

Unarmed

Origin

native

Lifespan

perennial

Growing Season

Warm season


Wetland Class

FACW

Wetland Coefficient of Conservatism

6

Prairie Coefficient of Conservatism

5

Field Characters

May be confused with Vernonia texana when sterile, but can be distinguished by its leaves which are linear and have edges which curl under, while those of Vernonia are strongly lance shaped and curl inward.

Cultural Information

Experiments by Nichols (1934) indicated that cold stratification slightly increased and speeded germination. Steffen (1997) reported improved germination with cold/stratification. Seeds average approximately 533,000 seeds/lb.

Animal Use

Helianthus angustifolius is a preferred plant and considered of high value as cattle forage, grazed throughout the season. Deer browse the foliage and quail and doves eat the seeds (Grelen and Hughes 1984). The following information is for the genus Helianthus: Animals that eat its seeds: Mourning dove, Eastern white-winged dove, Bobwhite quail, Gambel quail, Redwing blackbird, Crow, Eastern goldfinch, Purple grackle, Meadowlark, White-breasted nuthatch, Pyrrhuloxia, English sparrow, Grasshopper sparrow, Savannah sparrow, Tree sparrow, Eastern pocket gopher, Meadow mouse and various other species in the east. Animals that eat the plant: Muskrat, Antelope, White-tailed deer (Martin et al. 1951). This plant is a special value to native bees.

Natural History

A prairie species common in ditches and wet, disturbed areas of Louisiana and southeast Texas, but is also one of the most common forbs on many upland sites, including dry sandy ridges. Very aggressive in prairie restorations; consequently, it may be best to introduce this species a few years after completing a restoration.

Habitat

Flood plains and bottomlands.