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Field scabiosa

(Knautia arvensis)

Photo of field scaibiosa
Photo credit: Steve C. Garske

Herbaceous perennial in the teasel family, this species grows 1-3 feet tall. Plants are erect, hairy and sparsely branched with bluish/purplish flowers and deeply cut leaves.

Overview

Other names for this plant include:
  • Common names: blue buttons, meadow widow flower and gypsy’s rose
  • Scientific names: Scabiosa arvensis
Ecological threat:
  • Invader of prairies and grasslands; threatening Wisconsin's most impaired vegetation community, the tallgrass prairies.
  • This species is also commonly found along roadsides and disturbed areas.
  • A single plant can produce up to 2,000 seeds.
  • Deep taproots make this species very difficult to remove.
  • Infestations also result in significant declines in hay production and pasture land carrying capacities.
Overview map of field scabiosa classification in WI
Prohibited (red) counties

Classification in Wisconsin: Restricted

Species Assessment Groups (SAG) were assembled to recommend a legal classification for each species considered for NR 40. The recommendation for field scabiosa was based upon this literature review [PDF] developed by the department.

Identification

Leaves & stems: Stems have stiff hairs angled downwards, but are not prickly. Leaves are hairy. Lower leaves are usually coarsely toothed, or sometimes entire, and form a basal rosette. The upper leaves are opposite and deeply, pinnately cut.

Flowers: Blue to purple in color. The inflorescence is a dense composite of small florets clustered into a domed-shaped head resembling a single flower that occurs singly at the ends of stems. Below the flower head is a ring of narrow green bracts. Plants bloom June-September.

Fruits & seeds: The fruit is nut-like, cylindrical, very small and hairy.

Roots: Plants develop a deep taproot.

Control

Mechanical:
  • Cut or mow plants before they set seed to prevent the establishment of new plants.
  • Pulling is seldom effective due to the difficulty in removing the long, branched roots.
  • Infestations can be controlled by tilling and cultivation of other species. Heavily infested pastures/hayfields can be cultivated and rotated to an annual crop.
Chemical:
  • Escort (metsulfuron-methyl) at 20 gr/ha (8.0 gr/acre) provides excellent control. The escort should be applied to actively growing plants up to the early flower bud stage.

Photos

View field scabiosa pictures in our photo gallery!