Looking at Plants

Helianthus angustifolius

COMMON NAMES

Swamp Daisy, Swamp Sunflower, Narrowleaf Sunflower

Helianthus (hee-lee-AN-thus) – from the Greek for sun and flower

angustifolius (an-gus-tih-FO-lee-us) – having narrow leaves

GROUP 

Dicot

FAMILY 

Some taxonomists put in Asteraceae and others put in Compositae.

ORIGIN

Eastern United States

DESCRIPTION

Swamp Daisy is an evergreen herbaceous perennial that averages 4 to 6 feet in height with a comparable spread. It forms clumps with spreading rhizomes. It has a moderate to fast growth rate.

Leaves are evergreen, narrow, lanceolate, alternate in arrangement, simple, 3 to 6 inches long and ½ inch wide with dentate margins, rough textured, and dark green in color. It has pinnate veins, maroon stems, and coarse hairs on the lower stems.

The yellow daisy-like flowers are about 2 to 3 inches across with yellow rays and reddish brown to purple discs. It blooms from late summer to fall.

Fruit are brown and dry with seeds.

HARDINESS

It is hardy in USDA Zones 6 to 9. Freezes will kill to the ground to frequently resprout in the spring in warmer areas.

LIGHT

Full sun/part shade; it will be more dense and have more flowers in full sun.

SALT

Good Salt Spray Tolerance – it will grow near the shore but will benefit from a little protection such as behind the first row of plantings or behind the first dunes.

SOIL

It will grow on a wide variety of soils in the pH range of 5.5 to 7.5, even tolerating swamps and wetlands.

WATERING

It has moderate drought tolerance once established, but will tend to look a little better with irrigation in dry spells.

PROPAGATION

Seeds; division of rhizomes and plantlets

PRUNING

Pinch early on to promote branching, especially if growing in partial shade.

FERTILIZING

It has no special fertilizer needs. Unless a soil test suggests otherwise, a slow-release balanced analysis fertilizer applied per the product label will work.

PESTS

Fall Webworm, Saddleback Caterpillar

DISEASES

Powdery Mildew, Pythium Root Rot, Anthracnose, Botrytis, White Smut

DEER

Resistant

There are very few totally “deer-proof” plants. There are also, relatively speaking, few plants that are considered a preferred food supply of deer. Most plants fall in the big gap between. One of the biggest variables is the available preferred food supply in a given area. If their preferred food is scarce, they will munch on most anything.

OTHER

Good butterfly plant

USES

Specimen plant; butterfly garden; tall border/background; mass planting; wet areas

TOXICITY

A search of California Poison Control, Texas A&M University, Canadian Poisonous Plants Information System, University of Wisconsin, Poisonous Houseplants and Ornamentals - Merck Vet Manual, Purdue University - Guide to Toxic Plants in Forages, Poisonous Plants of the Southeastern United States - Alabama Cooperative Extension, Florida Poison Control, University of California, North Carolina State University, and The Cat Fanciers Association did not show this plant on any of their lists.

ASPCA lists Helianthus angustifolius as non-toxic to dogs, cats, and horses.