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Thin-leaved Sunflower

Helianthus x decapetalus

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Plant Profile

Flowering Months:
Asteraceae (Daisy)
Also in this family:
Alpine Blue Sow-thistle, Alpine Cotula, Alpine Fleabane, Alpine Saw-wort, Annual Ragweed, Annual Sunflower, Argentine Fleabane, Autumn Hawkbit, Autumn Oxeye, Beaked Hawksbeard, Beggarticks, Bilbao Fleabane, Black Knapweed, Black-eyed Susan, Blanketflower, Blue Fleabane, Blue Globe-thistle, Bristly Oxtongue, Broad-leaved Cudweed, Broad-leaved Ragwort, Brown Knapweed, Butterbur, Buttonweed, Cabbage Thistle, Canadian Fleabane, Canadian Goldenrod, Carline Thistle, Chalk Knapweed, Chamois Ragwort, Changing Michaelmas Daisy, Chicory, Chinese Mugwort, Chinese Ragwort, Coltsfoot, Common Blue Sow-thistle, Common Cat's-ear, Common Cudweed, Common Daisy, Common Dandelion, Common Fleabane, Common Goldenrod, Common Groundsel, Common Michaelmas Daisy, Common Mugwort, Common Ragwort, Common Wormwood, Coneflower, Confused Michaelmas Daisy, Corn Chamomile, Corn Marigold, Cornflower, Cotton Thistle, Cottonweed, Creeping Thistle, Daisy Bush, Dwarf Cudweed, Dwarf Thistle, Early Goldenrod, Eastern Groundsel, Eastern Leopardsbane, Elecampane, English Hawkweed, Fen Ragwort, Feverfew, Field Fleawort, Field Wormwood, Fox and Cubs, French Tarragon, Gallant Soldier, Garden Lettuce, Giant Butterbur, Glabrous-headed Hawkweed, Glandular Globe-thistle, Glaucous Michaelmas Daisy, Globe Artichoke, Globe-thistle, Goat's Beard, Golden Ragwort, Golden Samphire, Goldilocks Aster, Grass-leaved Goldenrod, Great Lettuce, Greater Burdock, Greater Knapweed, Grey-headed Hawkweed, Guernsey Fleabane, Hairless Blue Sow-thistle, Hairless Leptinella, Hairy Michaelmas Daisy, Harpur Crewe's Leopardsbane, Hawkweed Oxtongue, Heath Cudweed, Heath Groundsel, Hemp Agrimony, Highland Cudweed, Hoary Mugwort, Hoary Ragwort, Hybrid Knapweed, Intermediate Burdock, Irish Fleabane, Jersey Cudweed, Jerusalem Artichoke, Lance-leaved Hawkweed, Lavender-cotton, Leafless Hawksbeard, Least Lettuce, Leopardplant, Leopardsbane, Leptinella, Lesser Burdock, Lesser Hawkbit, Lesser Sunflower, London Bur-marigold, Magellan Ragwort, Marsh Cudweed, Marsh Hawksbeard, Marsh Ragwort, Marsh Sow-thistle, Marsh Thistle, Meadow Thistle, Melancholy Thistle, Mexican Fleabane, Milk Thistle, Mountain Everlasting, Mouse-ear Hawkweed, Musk Thistle, Narrow-leaved Cudweed, Narrow-leaved Hawkweed, Narrow-leaved Michaelmas Daisy, Narrow-leaved Ragwort, New England Hawkweed, New Zealand Holly, Nipplewort, Nodding Bur-marigold, Northern Hawksbeard, Norwegian Mugwort, Oxeye Daisy, Oxford Ragwort, Pearly Everlasting, Perennial Cornflower, Perennial Ragweed, Perennial Sow-thistle, Perennial Sunflower, Pineapple Mayweed, Plantain-leaved Leopardsbane, Ploughman's Spikenard, Plymouth Thistle, Pontic Blue Sow-thistle, Pot Marigold, Prickly Lettuce, Prickly Sow-thistle, Purple Coltsfoot, Rayed Tansy, Red Star Thistle, Red-seeded Dandelion, Red-tipped Cudweed, Robin's Plantain, Roman Chamomile, Rough Cocklebur, Rough Hawkbit, Rough Hawksbeard, Russian Lettuce, Safflower, Salsify, Saw-wort, Scented Mayweed, Scentless Mayweed, Sea Aster, Sea Mayweed, Sea Wormwood, Seaside Daisy, Shaggy Mouse-ear Hawkweed, Shaggy Soldier, Shasta Daisy, Shetland Mouse-ear Hawkweed, Shrub Ragwort, Sicilian Chamomile, Silver Ragwort, Slender Mugwort, Slender Thistle, Small Cudweed, Small Fleabane, Smooth Cat's-ear, Smooth Hawksbeard, Smooth Sow-thistle, Sneezeweed, Sneezewort, Spear Thistle, Spotted Cat's-ear, Spotted Hawkweed, Sticky Groundsel, Stinking Chamomile, Stinking Hawksbeard, Tall Fleabane, Tall Mouse-ear Hawkweed, Tansy, Trifid Bur-marigold, Tuberous Thistle, Tyneside Leopardplant, Viper's Grass, Wall Lettuce, Welsh Groundsel, Welted Thistle, White Butterbur, White Buttons, Willdenow's Leopardsbane, Winter Heliotrope, Wood Burdock, Wood Ragwort, Woody Fleabane, Woolly Thistle, Yarrow, Yellow Chamomile, Yellow Fox and Cubs, Yellow Oxeye, Yellow Star Thistle, Yellow Thistle, York Groundsel
Life Cycle:
Maximum Size:
180 centimetres tall
Gardens, meadows, riverbanks, riversides, woodland.

Yellow, many petals
There are 3 to 10 flowerheads. Flowerheads have up to 50 disc florets. There are between 8 and 12 petals per flower. Petals are 2 to 2.5cm (1 inch) long.
The fruit is seed-like and between 3.5 and 5mm long.
A clump-forming, deciduous perennial. The leaves are broadly lance-shaped with serrated margins. Leaf stalks are between 2 and 5cm long. Hairless stems.
Other Names:
Thinleaf Sunflower, Thin-leaved Sunflower.
Frequency (UK):
Rarely seen  

Similar Species

Other Information


Helianthus x decapetalus, also known as the Thin-Leaved Sunflower, is a hybrid perennial herbaceous plant that is a cross between Helianthus decapetalus (Ten-Petal Sunflower) and Helianthus annuus (Common sunflower). It is known for its large, yellow, daisy-like flowers that bloom in late summer and early fall, and its thin, lance-shaped leaves. The plant can grow up to 4-6 feet tall and spread up to 2-3 feet. It is a hardy plant that can tolerate a wide range of soil and climatic conditions, and is often used as an ornamental plant in gardens and landscapes. It is also used in traditional medicine for its anti-inflammatory and antimicrobial properties. Helianthus x decapetalus is a relatively rare plant, as it is a natural hybrid, and not often found in cultivation.


The Thin-leaved Sunflower, Helianthus x decapetalus, is a hybrid species of sunflower that is native to North America. It is a perennial plant that belongs to the Asteraceae family and is a cross between the Sawtooth Sunflower (Helianthus grosseserratus) and the Thin-leaved Sunflower (Helianthus decapetalus).

Appearance and Characteristics

The Thin-leaved Sunflower can grow up to 6 feet tall and has thin, lance-shaped leaves that are 3 to 6 inches long. The plant produces bright yellow flowers that can measure up to 3 inches in diameter, with 8 to 10 petals. The center of the flower is composed of many small, dark brown disk flowers, which attract a wide range of pollinators such as bees, butterflies, and birds.

Growing and Maintenance

The Thin-leaved Sunflower is a hardy plant that grows well in full sun and well-drained soil. It is drought-tolerant and can withstand periods of extreme heat and cold, making it an excellent choice for gardens and landscapes. It is easy to propagate from seeds or stem cuttings and requires little maintenance, making it an ideal choice for gardeners who are looking for low-maintenance plants.

Ecological Value

The Thin-leaved Sunflower is a valuable plant for pollinators, especially bees and butterflies. It provides nectar and pollen, which are essential food sources for many species of insects. It also serves as a host plant for the larvae of some butterfly species such as the Silvery Checkerspot (Chlosyne nycteis) and the Gorgone Checkerspot (Chlosyne gorgone). The plant's seeds are also an important food source for birds such as the American Goldfinch (Spinus tristis) and the House Finch (Haemorhous mexicanus).

Cultural Significance

The Thin-leaved Sunflower has been used for medicinal purposes by Native American tribes for centuries. The plant's leaves and roots were used to treat a variety of ailments, including headaches, fever, and stomach problems. The plant was also used as a dye for textiles, and the seeds were used as a source of oil.

The Thin-leaved Sunflower is a beautiful and valuable plant that is easy to grow and maintain. Its ecological and cultural significance adds to its appeal, making it an excellent addition to any garden or landscape. Whether you're a seasoned gardener or a beginner, the Thin-leaved Sunflower is a plant that is sure to delight and impress.

Uses of Thin-leaved Sunflower

In addition to its ecological and cultural significance, the Thin-leaved Sunflower has several other uses:

  1. Ornamental Purposes: The Thin-leaved Sunflower's bright yellow flowers add a vibrant burst of color to any garden or landscape. The plant is also ideal for creating natural-looking borders or as a backdrop for other plants.

  2. Erosion Control: The Thin-leaved Sunflower is a useful plant for controlling erosion in areas with sandy or loose soil. The plant's deep root system helps to stabilize the soil, preventing erosion and creating a more stable environment for other plants to grow.

  3. Honey Production: The Thin-leaved Sunflower's nectar is an excellent source of food for honeybees, and the plant is often grown by beekeepers to produce honey.

  4. Biofuel: The Thin-leaved Sunflower's seeds contain oil, which can be extracted and used as a source of biofuel. The plant's high oil content makes it an attractive option for renewable energy production.

Conservation and Threats

The Thin-leaved Sunflower is not considered a threatened species, but it faces several threats that could impact its survival. Habitat loss and degradation are the primary threats to the Thin-leaved Sunflower, as the plant is often displaced by human activities such as development and agriculture. Invasive species are also a threat, as non-native plants can outcompete the Thin-leaved Sunflower for resources.

To protect the Thin-leaved Sunflower, conservation efforts should focus on preserving and restoring its natural habitat. This can be done through land management practices such as prescribed burns and invasive species removal. Increasing public awareness of the plant's ecological and cultural significance can also help to raise support for conservation efforts.

The Thin-leaved Sunflower is a valuable and versatile plant that has many uses and benefits. Its ecological and cultural significance, as well as its ease of cultivation, make it an ideal addition to any garden or landscape. Protecting the plant from threats such as habitat loss and degradation is essential to ensure its survival and continued benefits to the environment and human society.

Breeding and Genetics

The Thin-leaved Sunflower is a hybrid species, resulting from the cross-pollination of two different sunflower species: the Sawtooth Sunflower and the Thin-leaved Sunflower. Hybridization is a common breeding technique used to create new plant varieties with desirable traits.

Hybridization of sunflower species has led to the development of many new varieties, each with unique characteristics such as different flower colors, sizes, and growth habits. For example, the Dwarf Sunflower (Helianthus annuus 'Teddy Bear') is a popular ornamental sunflower variety that was developed through hybridization.

In addition to hybridization, sunflower breeding also involves the selection of plants with desirable traits and the use of molecular markers to identify and track these traits. Genetic engineering techniques are also being used to create sunflower plants with improved traits, such as increased resistance to pests and diseases.

Future Research and Applications

Research on the Thin-leaved Sunflower and other sunflower species has many potential applications, including the development of new plant varieties with improved traits and the discovery of new compounds with medicinal or industrial uses.

For example, sunflower oil is a valuable commodity, and research is being conducted to develop sunflower varieties with higher oil content and improved oil quality. Sunflower seeds are also being studied for their potential health benefits, such as their high levels of vitamin E and antioxidants.

In addition, sunflower plants are being investigated for their ability to remove contaminants from soil and water, a process known as phytoremediation. This application could be used to clean up contaminated sites and reduce environmental pollution.


The Thin-leaved Sunflower is a beautiful and valuable plant that has many ecological, cultural, and economic benefits. Its ease of cultivation, versatility, and unique genetic makeup make it an important species for research and breeding. Protecting and preserving the Thin-leaved Sunflower and other sunflower species is essential to ensure their continued contributions to the environment and human society