SafePlants

Common Knapweed: A Meadow Essential

Common Knapweed, also known as Black Knapweed or Hardheads, is a tough perennial wildflower frequently found in meadows.

Considerations for Pets

• The plant is thistle-like, which may present a potential hazard to pets due to its prickly nature.
• Knapweed produces a large quantity of seeds, which could be ingested by pets.

Considerations for Children

• The plant is thistle-like, which may present a potential hazard to children due to its prickly nature.

Nomenclature and Taxonomy

• Scientific Name: Centaurea nigra
• Common Names: Common Knapweed, Black Knapweed, Hardheads
• Family: Daisy Family (Asteraceae)

Morphological Characteristics

• Flower heads resemble thistles.
• Flower heads are single, flower-like capitula surrounded by involucral bracts.
• Capitula are typically 3-4.5 cm (1.2-1.8 inches) in diameter.
• Capitula flowers are violet-red, occasionally pink or white.
• Leaves and stems are spineless.
• Can grow tall, with multiple stems emerging from a single root crown.

Distribution and Habitat

• Common Knapweed is abundant, particularly in England.
• It is a wildflower essential to meadows.

Ecological Role

• A firm favorite of pollinating insects.
• Some Knapweed species are considered highly invasive and a nuisance.

Reproduction

• Reproduces primarily by seed.
• A single plant can produce a large number of seeds, ranging from 1,200 to 60,000 depending on the species.