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Black Knapweed

Centaurea nigra

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.
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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-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 Star Thistle, Yellow Thistle, York Groundsel
Type:
Flower
Life Cycle:
Perennial
Maximum Size:
1 metre tall
Habitats:
Cliffs, fields, gardens, grassland, hedgerows, lawns, meadows, roadsides, scrub, wasteland, woodland.

Flower:
֍
Purple, many petals
 
The flowers of Black Knapweed, known as "Centaurea nigra" in botanical terms, are a striking sight in British meadows and grasslands. These blooms, often seen in late summer, feature deep purple, almost black, florets that are surrounded by spiky, dark bracts. The intricate, thistle-like appearance of Black Knapweed flowers adds a touch of wild elegance to the countryside. They are a vital nectar source for pollinators, including bees and butterflies, making them an essential component of our native flora and contributing to the vibrant tapestry of the British countryside.
Fruit:
The fruit of Black Knapweed, scientifically known as "Centaurea nigra," consists of small, dark achenes. These achenes, often referred to as seeds, are encased in the plant's spiky, protective bracts, resembling a miniature fortress. The mature achenes are typically brown to black in colour and are dispersed by the wind, helping the plant to propagate in its natural habitats across the United Kingdom. The fruit of Black Knapweed, though inconspicuous compared to its striking flowers, plays a crucial role in the plant's lifecycle and contributes to the ecological diversity of British meadows and grasslands.
Leaves:
The leaves of Black Knapweed, or "Centaurea nigra," are lance-shaped and deeply lobed, featuring a distinctive dark green hue. These leaves are covered in fine hairs, which give them a slightly rough texture and help reduce water loss through transpiration. The basal leaves form a rosette close to the ground, while the stem leaves become progressively smaller and less lobed as they ascend the plant's tall, slender stems. The leaves of Black Knapweed are an integral part of its foliage, providing a verdant backdrop to the striking purple flowers and supporting various herbivorous insects and invertebrates that feed on them in the rich and diverse habitats of the United Kingdom.
Aroma:
The Black Knapweed, scientifically known as "Centaurea nigra," is not known for its fragrance. Unlike some other wildflowers that emit pleasant or distinctive scents to attract pollinators, Black Knapweed relies more on its striking appearance and nectar-producing capabilities to entice bees, butterflies, and other insects. While it may lack a discernible fragrance, its deep purple flowers and intricate form contribute to its charm and importance in the British countryside, where it serves as a vital resource for pollinators during the late summer months.
Other Names:
Common Knapweed, Hardheads, Lesser Knapweed.
Frequency (UK):
Common  

Similar Species

Other Information

Summary

Centaurea nigra, commonly known as black knapweed, is a species of flowering plant in the aster family. It is native to Europe but has been introduced and naturalized in many parts of the world, including North America. It is a perennial plant that produces large, showy, pink or purple 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, black 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

Black Knapweed, also known as Centaurea nigra, is a beautiful and hardy plant that is native to Europe and Western Asia. It is a member of the Asteraceae family, which includes daisies and sunflowers. Black Knapweed is a perennial herb that can grow up to one meter tall and is commonly found in dry grasslands, pastures, meadows, and along roadsides.

Appearance

Black Knapweed has a distinctive appearance, with deep purple or black flowers that bloom in mid to late summer. The flowers are borne on long, thin stems that rise above the foliage. The leaves are deeply divided and have a feathery appearance. The stem and leaves are covered in a fine layer of white hairs, which gives the plant a silvery appearance.

Uses

Black Knapweed has been used for centuries for its medicinal properties. The plant contains a variety of compounds that have anti-inflammatory, antiseptic, and astringent properties. Black Knapweed has been used to treat a variety of ailments, including sore throats, diarrhea, and skin conditions such as eczema and psoriasis.

In addition to its medicinal properties, Black Knapweed is also an important plant for wildlife. The flowers provide nectar and pollen for a variety of insects, including bees, butterflies, and moths. The leaves and stems provide food for a variety of animals, including rabbits and deer. Black Knapweed is also an important plant for birds, as the seeds are a source of food for many species.

Cultivation

Black Knapweed is a relatively easy plant to grow, and it is well-suited to dry, sunny locations. The plant prefers well-drained soil and can tolerate a wide range of soil types. Black Knapweed can be propagated from seed or by dividing established plants. The plant does not require much maintenance, although deadheading the flowers can help to prolong the blooming period.

More Information

Black Knapweed is also known for its ability to attract pollinators, making it a great addition to pollinator gardens. The deep purple flowers are particularly attractive to bees, and planting Black Knapweed can help to support bee populations in your area.

In addition to its medicinal uses, Black Knapweed has also been used in traditional European folklore for its supposed magical properties. It was believed that the plant could be used to ward off evil spirits and to protect against the evil eye. Black Knapweed was also used in love spells, and it was believed that carrying a sprig of the plant could bring good luck in love.

Black Knapweed is often used in herbal teas and tinctures, and it can also be used topically in salves and creams for skin conditions. However, it is important to note that like any medicinal plant, Black Knapweed should be used with caution and under the guidance of a qualified healthcare practitioner.

In some areas, Black Knapweed is considered to be a weed, as it can spread quickly and outcompete other plants. However, in other areas it is highly valued for its wildlife and medicinal benefits. If you are considering planting Black Knapweed in your garden, it is important to check with your local authorities to ensure that it is not considered an invasive species in your area.

Black Knapweed is also sometimes called Lesser Knapweed, to distinguish it from Greater Knapweed (Centaurea scabiosa), which is a related species that is larger and has pink flowers. While the two species are similar in many ways, they can be distinguished by their flowers and leaves.

In addition to its uses in herbal medicine, Black Knapweed has also been used for a variety of other purposes throughout history. The dried leaves and stems of the plant were once used to stuff mattresses and pillows, and the roots were used to make a red dye. Black Knapweed was also used as a natural insecticide, as the plant contains compounds that repel insects such as ants and moths.

Black Knapweed is also a popular plant for use in flower arrangements, as the deep purple flowers are both striking and long-lasting. The plant can be cut and used fresh, or the flowers can be dried for later use.

While Black Knapweed is generally considered to be a hardy and low-maintenance plant, it can sometimes be susceptible to fungal diseases such as rust and powdery mildew. These diseases can be prevented by providing good air circulation around the plants and avoiding overhead watering.

In summary, Black Knapweed is a versatile and useful plant that has many benefits for both people and wildlife. Whether you are interested in its medicinal properties, its cultural and historical significance, or its beauty in the garden, Black Knapweed is a plant that is definitely worth exploring further.

Some Facts about Black Knapweed

Here are some additional facts about Black Knapweed:

  • Black Knapweed is a hardy perennial that can grow up to one meter tall.
  • The deep purple or black flowers of Black Knapweed bloom in mid to late summer and are borne on long, thin stems.
  • Black Knapweed is native to Europe and Western Asia and is commonly found in dry grasslands, pastures, meadows, and along roadsides.
  • The leaves of Black Knapweed are deeply divided and have a feathery appearance, and the stem and leaves are covered in fine white hairs.
  • Black Knapweed has medicinal properties and has been used for centuries to treat a variety of ailments, including sore throats, diarrhea, and skin conditions such as eczema and psoriasis.
  • Black Knapweed is an important plant for wildlife, as the flowers provide nectar and pollen for a variety of insects and the leaves and stems provide food for animals such as rabbits and deer.
  • Black Knapweed is easy to grow and is well-suited to dry, sunny locations with well-drained soil.
  • Black Knapweed is sometimes considered to be a weed in some areas, as it can spread quickly and outcompete other plants.
  • Black Knapweed has been used in traditional European folklore for its supposed magical properties, including its ability to ward off evil spirits and bring good luck in love.
  • Black Knapweed has been used for a variety of purposes throughout history, including as a stuffing for mattresses and pillows, as a natural insecticide, and to make a red dye.

In summary, Black Knapweed is a fascinating and useful plant that has a long history of medicinal, cultural, and practical uses. Whether you are interested in its benefits for wildlife, its medicinal properties, or its beauty in the garden, Black Knapweed is a plant that is worth exploring further.


Videos

Video 1: Black Knapweed at Scout Scar (16th July 2022) and Worthington Lakes (12th July 2022).

 

Video 2: Black Knapweed filmed at Waitby Riggs Nature Reserve in Cumbria on the 27th August 2023.

 

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Distribution Map

Reproduced by kind permission of the BSBI.

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