Open the Advanced Search

Yellow Star Thistle

Centaurea solstitialis

Please keep in mind that it is illegal to uproot a plant without the landowner's consent and care should be taken at all times not to damage wild plants. Wild plants should never be picked for pleasure and some plants are protected by law.
For more information please download the BSBI Code of Conduct PDF document.


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, 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 Thistle, York Groundsel
Life Cycle:
Maximum Size:
1 metre tall
Fields, wasteland.

Yellow, many petals
Yellow flowerheads, up to 2cm wide. Light green bracts, covered in white down. The bracts have many long, needle-like, sharp spines. Pollinated by bees, flies, butterflies and moths.
The fruit is an achene (seed) with a tuft of hairs at one end. The fruit is 2 or 3mm long.
An annual or biennial, greyish-green plant. The basal rosette of leaves are not spiny. Basal leaves measure up to 15cm (6 inches) in length. The stem leaves are shorter. Leaves are covered in a cottony white down. All leaves are not toothed. The stems are winged.
Other Names:
Barnaby Thistle, Golden Star Thistle, St Barnaby's Thistle, Yellow Cockspur.
Frequency (UK):

Similar Species

Other Information


Centaurea solstitialis, also known as Yellow Starthistle, is a species of flowering plant in the Asteraceae family. It is native to the Mediterranean region but has been introduced and has become invasive in many parts of the world, including North America. The plant has yellow flowers and spiky leaves and grows to be about 2-3 feet tall. It is considered a noxious weed, it is toxic to horses and other grazing animals, and can cause neurological damage. It also competes with native plants and has a negative impact on biodiversity. It is difficult to control once established, and multiple methods may be needed to effectively manage infestations.


Yellow Star Thistle: The Invasive Plant Taking Over the West Coast

Yellow star thistle (Centaurea solstitialis) is a highly invasive plant species that is native to the Mediterranean region but has been introduced to various parts of the world, including the western United States. This plant is highly prized for its beautiful yellow flowers, but its impact on the environment has been anything but positive. In this blog post, we will discuss the characteristics of yellow star thistle, its impact on the environment, and what you can do to help prevent its spread.

Identifying Yellow Star Thistle

Yellow star thistle is a spiny, annual plant that can grow up to four feet tall. It has yellow, composite flowers that are about one inch in diameter and are surrounded by spiny bracts. The plant's leaves are long and narrow, with a soft, velvety texture. The stems are green, slightly hairy, and also spiny. The spiny nature of this plant makes it difficult to remove and provides it with protection from herbivores.

Impact on the Environment

Yellow star thistle is highly invasive, and it has the potential to cause significant harm to the environment. It is a drought-tolerant plant that can outcompete native vegetation, reducing biodiversity and altering ecosystems. Once established, yellow star thistle can spread rapidly, covering large areas and preventing the growth of other plants. This can lead to soil erosion and decreased soil fertility, as well as reducing the habitat available for wildlife.

Yellow star thistle is also toxic to horses and other livestock. The spines on the plant can cause injury to animals, and the plant's seeds are toxic if ingested. This can lead to decreased livestock productivity and reduced income for farmers and ranchers.

Preventing the Spread of Yellow Star Thistle

The best way to prevent the spread of yellow star thistle is to prevent it from being introduced to new areas. This can be done by cleaning vehicles, clothing, and equipment before moving from one area to another. It's also important to avoid planting yellow star thistle in your own yard, as it can easily spread to nearby areas.

If you do find yellow star thistle on your property, it's important to take action to remove it as soon as possible. This can be done manually or with the use of herbicides. However, care should be taken when using herbicides, as they can have unintended consequences and harm other plants and wildlife. It's best to consult with a professional or local resource for guidance on the best method for removing yellow star thistle from your property.

Yellow star thistle is a highly invasive plant that can have a significant impact on the environment and wildlife. To prevent its spread, it's important to avoid planting it in your own yard and to take steps to remove it if you find it on your property. By working together, we can help protect our natural areas and preserve the beauty of the western United States.

Controlling Yellow Star Thistle

There are a few different methods that can be used to control yellow star thistle, including manual removal, herbicides, and biological control.

Manual removal involves pulling or digging up the plants by hand. This method is effective for small infestations, but it can be time-consuming and labor-intensive.

Herbicides can be used to control yellow star thistle, but they should be used with caution. Herbicides can harm non-target plants and wildlife, so it's important to follow label instructions and to consult with a professional before using them.

Biological control is another option for controlling yellow star thistle. This involves introducing natural predators or parasites that feed on or damage the plant, reducing its ability to spread. One example of a biological control agent for yellow star thistle is the seed head weevil (Rhinocyllus conicus). This insect feeds on the seeds of the plant, reducing its ability to reproduce and spread.

Restoration Efforts

While yellow star thistle can be difficult to control once established, there are efforts underway to restore areas that have been affected by this invasive species. Restoration efforts often involve removing yellow star thistle and replanting native vegetation. This helps to restore the balance of the ecosystem, increase biodiversity, and improve soil health.

One such effort is the Yellow Star Thistle Partnership, which was established in 2002 to coordinate the efforts of organizations and individuals working to control yellow star thistle in California. This partnership has helped to increase awareness of the problem and to coordinate efforts to control and remove the plant.

Yellow star thistle is a highly invasive plant that can cause significant harm to the environment and wildlife. There are various methods that can be used to control yellow star thistle, including manual removal, herbicides, and biological control. Restoration efforts are also underway to help restore areas that have been affected by this invasive species. By working together, we can help protect our natural areas and preserve the beauty of the western United States.

The Importance of Early Detection

Early detection of yellow star thistle is critical in controlling its spread. The longer it is allowed to establish in an area, the more difficult it becomes to remove. Therefore, it is important to be vigilant and to report any sightings of yellow star thistle as soon as possible.

There are several organizations that provide information on how to identify yellow star thistle and how to report it, including the Yellow Star Thistle Partnership in California and the Oregon Invasive Species Council. These organizations can provide guidance on how to remove the plant and how to participate in restoration efforts.

The Role of Land Managers and Landowners

Land managers and landowners have an important role to play in controlling yellow star thistle. By taking steps to prevent the spread of this invasive species and to remove it from their property, they can help protect the environment and prevent the plant from spreading to new areas.

Land managers can also participate in restoration efforts and work with organizations to control yellow star thistle on public lands. Landowners can also participate in these efforts by reporting any sightings of the plant and taking steps to remove it from their property.

The Future of Yellow Star Thistle

Yellow star thistle is a persistent and invasive species that can have a significant impact on the environment. However, with continued efforts to control its spread and to restore affected areas, it is possible to minimize its impact and to preserve the natural beauty of the western United States.

It is important to remember that yellow star thistle is not the only invasive species that poses a threat to the environment. There are many other invasive species that can cause harm to our natural areas, and it is important to be vigilant and to take steps to prevent their spread. By working together, we can help protect our natural heritage and preserve the beauty of the western United States for future generations.

Distribution Map

Reproduced by kind permission of the BSBI.

Click to open an Interactive Map