Thinleaf Sunflower Helianthus decapetalus
Other Common Name(s):
Previously known as:
- Helianthus scrophulariifolius
- Helianthus tenuifolius
- Helianthus tracheliifolius
- Phonetic Spelling
- hee-lee-AN-thus de-kap-UH-tal-us
- Description
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The ten-petaled sunflower is a rhizomatous perennial wildflower in the daisy family (Asteraceae) and is native to eastern Canada and the eastern and central United States. It is typically found in woodlands, forest borders, meadows, and slightly shaded areas along rivers, roadsides, and thickets. In North Carolina, this plant is typically found in the Mountains and Piedmont. It is rarely found in the Coastal Plains, although it is known to exist in Greene and Pitt Counties. It grows erect, 3 to 5 feet tall, with a light green stem and large dark green, thin, flexible, lanceolate to ovate leaves. Yellow flowerheads appear at the terminal end of the stem and are up to 3 inches in diameter. The flowers have 8 to 12 bright yellow petal-rays with a central disk of numerous yellow, tubular, disk florets. Blooms appear from July through October. The specific epithet, decapetalus, is derived from Greek, meaning ten-petaled.
This easy-to-grow plant prefers full sun, partial shade, or dappled shade. It will tolerate a variety of soil types as long as they are moist, fertile, well-drained soils with a neutral pH. This perennial is winter hardy in zones 4 through 9. Strong winds may damage the stems; best planted in a sheltered location. Propagation by seeds in the spring and division in the fall. This plant can spread aggressively via its rhizomes.
The ten-petaled sunflower is a high-value plant for wildlife, providing food for pollinators, birds, and mammals. The flowers attract bees, butterflies, and other pollinators. Many birds and small mammals enjoy eating the seeds from the seedheads.
This attractive plant will add color in the landscape and can be used in a naturalized area, woodland edge, or meadow. Great for naturalizing. Consider for use in a cottage, butterfly, or wildflower garden.
Quick ID Hints:
- Large and narrow leaves
- The leaf margins have long and pointed teeth
- The leaf tips are usually long and slender
- The floral bracts are long and slender
- 8 to 12 yellow petal-rays and more than 40 yellow tubular disk florets
Insects, Diseases, and Other Plant Problems: No significant insect or disease problems. May be susceptible to powdery mildew. Rabbits and deer like to browse the plant.
Click here to see a calendar of planting schedules, time-to-harvest, and recommended spacing.
- See this plant in the following landscape :
- Cultivars / Varieties:
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- Tags:
- Cultivars / Varieties:
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- Tags:
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Attributes:
- Genus:
- Helianthus
- Species:
- decapetalus
- Family:
- Asteraceae
- Life Cycle:
- Perennial
- Recommended Propagation Strategy:
- Division
- Seed
- Country Or Region Of Origin:
- Eastern Canada and North Central and Eastern United States
- Distribution:
- Native: United States--AL, AR, CT, DE, DC, GA, IL, IN, IA, KY, LA, ME, MD, MA, MI, MS, MO, NH, NJ, NY, NC, OH, OK, PA, RI, SC, TN, VT, VA, WV, and WI; Canada--New Brunswick, Ontario, and Quebec. Introduced: Austria, Belgium, Germany, Hungary, Myanmar, Norway, Northwest Balkan Peninsula, Poland, Romania, and Switzerland.
- Wildlife Value:
- Bees, butterflies, and other pollinators visit the flowers. This is a larval host plant that supports the Silvery Checkerspot (Chlosyne nycteis). The Silvery Checkerspot has at least 1-2 broods in the north from June-July; in the deep south and Texas, they have as many as 3-4 broods from May through September. It is also the larval host for the Painted Lady. Seeds are eaten by game and songbirds. Small mammals will browse the leaves.
- Play Value:
- Attractive Flowers
- Attracts Pollinators
- Colorful
- Easy to Grow
- Wildlife Food Source
- Wildlife Larval Host
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Whole Plant Traits:
- Plant Type:
- Native Plant
- Perennial
- Wildflower
- Habit/Form:
- Erect
- Growth Rate:
- Medium
- Maintenance:
- Medium
- Texture:
- Coarse
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Cultural Conditions:
- Light:
- Dappled Sunlight (Shade through upper canopy all day)
- Full sun (6 or more hours of direct sunlight a day)
- Partial Shade (Direct sunlight only part of the day, 2-6 hours)
- Soil Texture:
- High Organic Matter
- Loam (Silt)
- Sand
- Soil pH:
- Neutral (6.0-8.0)
- Soil Drainage:
- Good Drainage
- Moist
- Occasionally Dry
- Available Space To Plant:
- 12 inches-3 feet
- NC Region:
- Coastal
- Mountains
- Piedmont
- USDA Plant Hardiness Zone:
- 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
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Fruit:
- Display/Harvest Time:
- Fall
- Fruit Length:
- < 1 inch
- Fruit Width:
- < 1 inch
- Fruit Description:
- The fruit is an oblong, slightly flattened cypsela, measuring about 1/8 inch long. Displays from August to November
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Flowers:
- Flower Color:
- Gold/Yellow
- Flower Inflorescence:
- Head
- Flower Value To Gardener:
- Showy
- Flower Bloom Time:
- Fall
- Summer
- Flower Shape:
- Radial
- Flower Petals:
- 7 - 20 petals/rays
- Flower Size:
- 1-3 inches
- Flower Description:
- The bright yellow flower heads are 2 to 3.5 inches across and have 8 to 12 ray florets, surrounding a central disk that contains 40 or more yellow, tubular disk florets. The base of each flower head consists of several overlapping light green bracts. Blooms from July to October.
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Leaves:
- Leaf Color:
- Green
- Leaf Feel:
- Rough
- Leaf Type:
- Simple
- Leaf Arrangement:
- Alternate
- Opposite
- Leaf Shape:
- Lanceolate
- Ovate
- Leaf Margin:
- Serrate
- Hairs Present:
- No
- Leaf Length:
- 3-6 inches
- Leaf Width:
- 1-3 inches
- Leaf Description:
- The leaves are dark green and rough on the upper surface, lanceolate to ovate, with serrate margins. The undersides of the leaves are light green and mostly hairless. They measure up to 7 inches long and 3 inches wide, and have long, slender tips. The lower and middle leaves are arranged opposite, and the upper leaves are alternate. The petioles measure 0.5 to 1.5 inches long and are slightly winged at the leaf blade, but narrower at the stem.
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Stem:
- Stem Color:
- Green
- Purple/Lavender
- Red/Burgundy
- Stem Is Aromatic:
- No
- Stem Surface:
- Hairy (pubescent)
- Stem Description:
- Stems are erect with occasional branching, and they may be light green, pale reddish-green, or purple. Short bristly hairs are found on the upper stems; however, the lower stems are smooth and sometimes glaucous.
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Landscape:
- Landscape Location:
- Meadow
- Naturalized Area
- Woodland
- Landscape Theme:
- Butterfly Garden
- Native Garden
- Pollinator Garden
- Attracts:
- Butterflies
- Pollinators
- Small Mammals
- Songbirds
- Problems:
- Weedy
