Helianthus silphioides

Species Native to Missouri
Common Name: rosinweed sunflower 
Type: Herbaceous perennial
Family: Asteraceae
Native Range: Southeastern and southcentral United States
Zone: 5 to 9
Height: 3.00 to 10.00 feet
Spread: 1.00 to 5.00 feet
Bloom Time: August to October
Bloom Description: Yellow rays and reddish-purple center disks
Sun: Full sun
Water: Dry to medium
Maintenance: Low
Suggested Use: Naturalize
Flower: Showy, Good Cut
Attracts: Birds, Butterflies
Tolerate: Deer, Drought, Erosion, Clay Soil, Dry Soil

Culture

Grow in average, moderately fertile, dry to medium moisture, well-drained soils in full sun. Tolerates a wide range of soils, including sandy soils, humusy loams and clays. Tolerates dry soils and drought. Easily grown from seed and may self-seed in the garden.

Noteworthy Characteristics

Helianthus silphioides, commonly called rosinweed sunflower or Ozark sunflower, is an herbaceous perennial that, as the specific epithet suggests, is very similar in appearance to plants in the genus Silphium. It is native to the south central U.S. (Illinois, Missouri, Kentucky, Oklahoma, Arkansas, Tennessee, Louisiana, Mississippi and Alabama). Sunflowers (3” diameter) with yellow rays and dark reddish-purple center disks bloom from mid/late summer to fall (August – October) on hispid stems rising to 3-10’ tall. Opposite, broad ovate to suborbicular, basal and cauline leaves (2-6” long) are blunt-tipped or rounded. Leaves on the upper portions of the plant are substantially smaller and sparser. In Missouri, rosinweed sunflower is typically found in alluvial soils near streams, fields, wood margins, dry upland open woods, thickets and roadsides in the far south to southeastern part of the state (Steyermark).

Genus name comes from the Greek words helios meaning sun and anthos meaning flower.

Specific epithet means similar in appearance to plants in the genus Silphium.

Problems

No serious insect or disease problems. Taller plants may need some staking or other support in exposed areas.

Garden Uses

Sunny borders, wild or native plant gardens, cottage gardens, naturalized areas, meadows or prairies.