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Greater Knapweed

Centaurea scabiosa

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.

Contents

Plant Profile

Flowering Months:
JAN  FEB  MAR  APR  MAY  JUN  JUL  AUG  SEP  OCT  NOV  DEC
Order:
Asterales
Family:
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, 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 Star Thistle, Yellow Thistle, York Groundsel
Type:
Flower
Life Cycle:
Perennial
Maximum Size:
150 centimetres tall
Habitats:
Cliffs, fields, gardens, grassland, hedgerows, meadows, roadsides, scrub, seaside, wasteland, woodland.

Flower:
֍
Purple, many petals
 
The flowers of Greater Knapweed in the UK are characterized by their striking and intricate appearance. Each flower head is composed of tubular, disc-shaped florets surrounded by distinctive, spiky bracts. The florets can vary in color, ranging from deep purple to mauve, and they form a dense, rounded cluster at the center of the flower head. The outer bracts are often longer and more noticeable, giving the flower head a spiky and textured appearance. The bloom has an overall captivating and robust quality, attracting pollinators such as bees and butterflies. Greater Knapweed's flowers contribute to the biodiversity and visual allure of meadows, grasslands, and other natural habitats across the UK.
Fruit:
The fruit of Greater Knapweed in the UK is an achene, a small, dry seed with a single seed enclosed in a hard outer layer. After the flowering season, the plant produces these small, brown achenes, which are dispersed by the wind. The achene is often attached to a fluffy pappus, a structure that aids in wind dispersal. As the wind carries the lightweight achenes away from the plant, they can settle in new locations, contributing to the natural spread and colonization of Greater Knapweed in different habitats. The fruiting stage is a crucial part of the plant's life cycle, ensuring its reproductive success and adaptation to diverse environments in the UK.
Leaves:
The leaves of Greater Knapweed in the UK are lance-shaped and deeply lobed, creating an overall pinnate or feathery appearance. These leaves are typically hairy, providing a textured and slightly rough feel. The edges of the leaves may appear toothed or serrated, adding to their distinctive look. The leaf color is generally a deep green, and the arrangement is alternate along the stem. The foliage forms a basal rosette, particularly in the early stages of the plant's growth. The leaves play a crucial role in photosynthesis, capturing sunlight to support the plant's energy needs. The unique leaf characteristics contribute to the overall aesthetic appeal and ecological adaptations of Greater Knapweed in various habitats across the United Kingdom.
Aroma:
Greater Knapweed does not typically have a strong or distinctive fragrance. The plant is more renowned for its visual appeal with vibrant flowers, rather than for any notable scent. The focus of Greater Knapweed's allure lies in its colourful blooms and ecological contributions, making it an attractive wildflower in meadows, grasslands, and other natural habitats in the United Kingdom. While it may not be known for fragrance, it remains a visually striking and ecologically valuable species in the British flora.
Other Names:
Greater Centaury, Rough Knapweed, Scabious Knapweed.
Frequency (UK):
Occasionally seen  

Similar Species

Other Information

Summary

Centaurea scabiosa, commonly known as rough knapweed or greater knapweed, is a species of flowering plant in the aster family. It is native to Europe and Asia, but it has naturalized in many parts of the world, including North America. It is a perennial plant that produces large, showy, pink, purple or blue flowers on tall, stiff stems. The leaves are deeply lobed, and the plant forms clumps of foliage. It prefers full sun and well-drained soil to grow well. It is often found in meadows, pastures, roadsides, and waste areas. It is drought tolerant and can be grown in poor soil. It is often used in wildflower meadows, mixed borders, and cottage gardens. However, rough knapweed can be invasive and can crowd out native plants, so it's important to keep an eye on it and control it if necessary.

Blog

Greater Knapweed, also known as Centaurea scabiosa, is a herbaceous perennial plant that belongs to the Asteraceae family. It is native to Europe and Western Asia but has been introduced in other parts of the world, including North America, where it is considered an invasive species in some areas.

Appearance

The Greater Knapweed plant grows up to 1.5 meters in height and has a branched stem with numerous leaves. The leaves are greyish-green, lance-shaped, and deeply lobed. The plant produces large, showy flower heads that are 3-5 cm in diameter. The flower heads have a cone-shaped center that is surrounded by long, spiky bracts that are purple in color. The petals of the flowers are also purple and are arranged in a star-like pattern.

Habitat and Growing Conditions

Greater Knapweed thrives in open meadows, grasslands, and along roadsides. It prefers well-drained soil and can tolerate a wide range of pH levels. The plant can grow in full sun or partial shade and can tolerate drought conditions. It is a hardy plant that can survive in temperatures as low as -20°C.

Uses

Greater Knapweed has several uses. Historically, it was used for medicinal purposes. The plant was believed to have diuretic properties and was used to treat various conditions such as bladder and kidney problems. The leaves were also used as a poultice to treat skin ulcers and wounds.

In addition to its medicinal uses, Greater Knapweed is also an excellent ornamental plant. It is often grown in gardens for its showy flowers, which attract bees, butterflies, and other pollinators. The plant is also used in cut flower arrangements.

Conservation

Greater Knapweed is not considered an endangered species. However, in some areas, it has been displaced by invasive plant species. It is important to control the spread of invasive plants to protect the native flora and fauna.

Ecological Benefits

Greater Knapweed is an important plant for pollinators, including bees, butterflies, and moths. The showy flowers of the plant provide a rich source of nectar and pollen, making it an attractive food source for these insects. Greater Knapweed also provides habitat for a variety of insects and other invertebrates, which in turn provide food for birds and other animals.

Cultural Significance

Greater Knapweed has been used in folklore and mythology in various cultures. In ancient Greece, it was believed that the plant had medicinal properties and was used to treat various ailments. In Celtic mythology, Greater Knapweed was associated with the goddess Brigid and was believed to have protective powers. The plant has also been used in traditional medicine in Europe and Asia.

Garden Uses

Greater Knapweed is a popular plant in gardens and is often used in cottage gardens, wildflower meadows, and other naturalistic planting schemes. The plant is easy to grow from seed and is a good choice for beginner gardeners. It is also relatively low maintenance and can tolerate a wide range of growing conditions.

Propagation

Greater Knapweed can be propagated from seed, which should be sown in the autumn or early spring. The seeds should be sown directly into the ground, as the plant does not transplant well. The soil should be well-drained and free of weeds. The seeds will germinate in 1-3 weeks, and the plants will begin to flower in their second year.

Control of Invasive Spread

As mentioned earlier, Greater Knapweed has the potential to become invasive in some areas. It is important to control the spread of the plant to protect native flora and fauna. This can be done by removing the plant before it sets seed or by cutting back the plant before the seeds are dispersed. Hand weeding and mulching can also be effective in controlling the spread of the plant.

In areas where Greater Knapweed is considered an invasive species, it is important to take additional measures to control its spread. This may include using herbicides, grazing animals, or burning the area to remove the plant. It is important to consult with local authorities or environmental organizations for guidance on how to control invasive species in your area.

Conclusion

Greater Knapweed is a beautiful and versatile plant that has several uses. It is an important source of food for pollinators and provides habitat for a variety of insects and other invertebrates. It is also an excellent ornamental plant and is often grown in gardens. However, it is important to be aware of its potential for invasive spread and take measures to control its growth in areas where it is not native. By planting Greater Knapweed responsibly and sustainably, we can enjoy its beauty and benefits while also protecting the environment.


Facts about Greater Knapweed

  • Greater Knapweed, also known as Centaurea scabiosa, is a herbaceous perennial plant that is native to Europe and Western Asia.
  • The plant produces large, showy flower heads that are 3-5 cm in diameter with purple petals arranged in a star-like pattern.
  • Greater Knapweed is an important plant for pollinators, providing a rich source of nectar and pollen.
  • The plant has historical uses for medicinal purposes and is still used in traditional medicine in some parts of the world.
  • Greater Knapweed is also an excellent ornamental plant and is often grown in gardens for its showy flowers.

Greater Knapweed is a versatile and attractive plant that has several ecological, cultural, and medicinal benefits. It is an important source of food for pollinators and provides habitat for a variety of insects and other invertebrates. The plant has historical uses in traditional medicine and is also an excellent ornamental plant. However, it is important to be aware of its potential for invasive spread and take measures to control its growth in areas where it is not native. By planting Greater Knapweed responsibly and sustainably, we can enjoy its beauty and benefits while also protecting the environment.


Videos

Video 1: Marbled White butterfly filmed on Greater Knapweed at Newmarket, Suffolk on the 25th June 2022.

 

Video 2: Greater Knapweed filmed at Bourton-on-the-water in Gloucestershire on the 24th June 2023.

 

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Distribution Map

Reproduced by kind permission of the BSBI.

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