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Guernsey Fleabane

Conyza sumatrensis

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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, 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, Thin-leaved Sunflower, 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:
2 metres tall
Fields, gardens, meadows, roadsides, towns, wasteland.

White, many petals
Clusters of white flowers. Similar to Canadian Fleabane (Conyza canadensis) but the clusters are more pyramidal in shape and the bracts are a greyer green. Also, the bracts are downy.
A seed with a yellowish-white tuft of hairs at one end. The seeds are dispersed by the wind.
The leaves are lobed and shaped like long, thin dandelion leaves. They are also rough and crinkled. Similar to Canadian Fleabane (Conyza canadensis) except that the leaves are stronger toothed, greyer and edged with hooked hairs. Annual.
Other Names:
Broad-leaved Fleabane, Fleabane, Sumatran Fleabane, Tall Fleabane, White Horseweed.
Frequency (UK):
Occasionally seen  

Similar Species

Other Information


Conyza sumatrensis, also known as Sumatra fleabane, is an annual herb in the Asteraceae family. It is native to Southeast Asia, particularly Sumatra and Java islands, but it is now widely distributed in many parts of the world, including Africa, Asia and North America. It is considered as a weed and invasive species in some regions.

Conyza sumatrensis usually grows to a height of 60-120 cm and it has a branching stem that is covered with fine hair. The leaves are oblong, 1-2 cm long and covered with fine hair. The small, yellow-white composite flowerheads are arranged in a terminal corymb. The plant blooms throughout the summer and the fall.

This plant is quite adaptable and can grow in a variety of soil types and in full sun or partial shade. It can also tolerate drought and poor soil. It can be found in a wide variety of habitats, including pastures, meadows, roadsides, waste places and along railroads. It's also a common weed in cultivated fields, gardens, and nurseries.

Like Conyza bilbaoana, C. sumatrensis is considered invasive and difficult to control, once it establishes in an area, it can outcompete native plants, thus reducing biodiversity. It is propagated by seeds, which are dispersed by wind, animals, and water. To control it, manual removal, using mulch or mulch combined with herbicide application are some of the methods.


Guernsey Fleabane, also known as Conyza sumatrensis, is a herbaceous plant belonging to the Asteraceae family. It is a common weed found in many parts of the world, including Guernsey, where it is named after.

Appearance and Habitat

Guernsey Fleabane is an annual plant that can grow up to 2 meters tall. Its stem is erect, branching, and covered in fine white hairs. The leaves are simple, alternate, lanceolate, and also covered in fine hairs. The flowers are small, white or pale pink, and appear in clusters at the end of the stem.

Guernsey Fleabane can grow in various habitats, including gardens, roadsides, fields, and waste areas. It thrives in disturbed soils and is a common weed in agricultural and horticultural settings.

Medicinal Properties

Guernsey Fleabane has been used in traditional medicine for its medicinal properties. It is believed to have antimicrobial, anti-inflammatory, analgesic, and antipyretic properties.

The plant contains various compounds, including flavonoids, alkaloids, and terpenoids, which contribute to its medicinal properties. It has been used to treat a wide range of ailments, including fever, headache, toothache, diarrhea, and respiratory infections.

Recent research has also shown that Guernsey Fleabane may have potential as an anti-cancer agent. Studies have found that the plant contains compounds that can inhibit the growth of cancer cells.

Cultural Significance

Guernsey Fleabane is named after the island of Guernsey, where it is a common weed. The plant has become a symbol of the island and is featured in its coat of arms. It is also depicted on some of the island's stamps and coins.

Guernsey Fleabane has also been used in traditional folklore. It was believed that the plant could ward off fleas, and it was often used as a strewing herb in houses and barns.

Guernsey Fleabane, Conyza sumatrensis, is a herbaceous plant with medicinal properties. It is a common weed found in many parts of the world, including Guernsey, where it is named after. The plant has been used in traditional medicine for its antimicrobial, anti-inflammatory, analgesic, and antipyretic properties. It is also a symbol of the island of Guernsey and has been used in traditional folklore. Further research is needed to fully understand the potential of Guernsey Fleabane as a medicinal plant.

More about Guernsey Fleabane

While Guernsey Fleabane has been used in traditional medicine, it should be noted that there is limited scientific research on its effectiveness and safety. Like with any medicinal plant, it is important to consult a healthcare professional before using Guernsey Fleabane for medicinal purposes.

Guernsey Fleabane's ability to inhibit the growth of cancer cells is an area of research that holds promise. However, further studies are needed to determine the specific compounds responsible for this effect and how they may be used to develop new treatments for cancer.

As a common weed, Guernsey Fleabane can have a negative impact on agricultural and horticultural crops. It is important to manage weed populations to prevent them from competing with desirable plants for resources.

In addition to its medicinal properties and cultural significance, Guernsey Fleabane also has ecological value. The plant can provide habitat and food for pollinators and other wildlife.

Guernsey Fleabane's traditional use in strewing in houses and barns to ward off fleas is an interesting example of how plants have been used for pest control for centuries. While the effectiveness of Guernsey Fleabane for this purpose has not been scientifically validated, there is research on the use of other plants for pest control. For example, some essential oils derived from plants such as peppermint, lavender, and thyme have been found to repel pests such as mosquitoes and flies.

Guernsey Fleabane's ability to grow in disturbed soils and its fast growth rate can make it a challenging weed to control. Traditional methods of weed control, such as hand weeding or mechanical cultivation, may be effective for small-scale management. However, herbicides may be necessary for larger infestations. It is important to use herbicides according to label instructions and to follow safety precautions when handling these chemicals.

Guernsey Fleabane's appearance is similar to that of other plants in the Conyza genus, such as Conyza canadensis, also known as Canadian Fleabane, and Conyza bonariensis, also known as hairy fleabane. These plants can be difficult to differentiate, but their characteristics and distribution may vary depending on the species.

In conclusion, Guernsey Fleabane is a fascinating plant with a rich history and potential for various applications. While it may be considered a weed in some contexts, it has medicinal, ecological, and cultural significance. Further research on its properties and management strategies may help us better understand and utilize this plant.


Guernsey Fleabane filmed at Marshside, Southport, Lancashire on the 15th July 2023.


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Distribution Map

Reproduced by kind permission of the BSBI.

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