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Field scabious flower heads
  • Perennial grows up to 1.5 meters tall

  • Introduced from Eurasia as an ornamental

  • Also known as bluebuttons.

Field scabious.webp

Flield scabious
(Knautia arvense)

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Quick Identification

  • Solitary violet flower heads

  • Ring of narrow, green floral bracts

  • Leaves deeply lobed into 5 to 15 narrow segments

  • Lower part of plant is bristly and hairy

  • Distinctive V shaped branching pattern on main

Field scabious competes with native species, and reduces the productivity of agricultural land, including pasture carrying capacity and crop yields.

Hand pulling or digging is effective if entire root is removed. Best done when soil is moist. Wear gloves to avoid skin contact.  If any portion of flower is beginning to emerge, or if seed heads are formed, pick, bag, and remove. Selective herbicides are effective.

Solitary flowers are up to 4 cm and are found on the ends of long, leafless stalks and are violet blue to pale purple in colour. Below each flower head are 8 to 12 sepals and a ring of narrow green bracts. Florets have 4 to 5 lobed petal tubes, four stamens, and a single pistil.

Leaves & Stems
During the first year, plants are low growing rosettes.  Rosette leaves are highly variable and could have smooth edges or can be deeply lobed. In the second year stalk leaves are 10 to 25 cm long, opposite, and lobed into 5 to 15 narrow segments. 

Field scabious 1.webp

Reproduction & Dispersal
Plants reproduce by seed. Most seeds fall close to parent plant but animals also facilitate seed dispersal in their manure.

Rectangular, light brown, four-sided seeds are densely covered with long hairs.  One plant can produce 200,000 seeds that may remain viable in the soil for several years.

Woody taproot that often has branches.

Preferred Habitat
Roadsides, pastures and fields. Prefers nutrient-rich and moderately moist to dry loam soils, but also establishes in gravelly soils. Field scabious can invade undisturbed plant communities.

Interesting Facts
Still sold as an ornamental and butterfly attractant. Potential impacts to riparian areas by excluding native plants.

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