Knautia arvensis (L.) J.M. Coult.

Field scabious, blue buttons, field scabiosa

Field scabious is native throughout Europe. It has become naturalized in North America, after escaping from gardens, becoming overly common to invasive in some midwestern states.

Plants: 12–31″ (30–80 cm) tall. Stems branch near the top, and are densely hairy and green to purplish, often with purple spots.

Leaves: Opposite, on short petioles or none at all, lanceloate-elliptic, gray-green, with soft hairs. The lowest leaves are up to 1″ (3 cm) long. Stem leaves are pinnately divided, with a large terminal leaflet.

Flowers: Single flowers atop long stems are irregular, blue-violet, flattish or rounded, 1–1½″ (2.5–3.8 cm) around. Each flower contains 85-100 florets. Florets near the center are funnel-shaped, with four lobes. Edge florets are larger and more irregular. Four violet-tipped stamens appear near the center of each flower. There are 8-12 sepals at the base of each flower. The calyx beneath the flower is small. Flowers appear June-August.

Habitats: Along river banks and roadsides, and in meadows, pastures, waste ground, and well-lit forests.

Fruits: A nutlet ~3/16 ⨉ 1/16″ (5–6 ⨉ 2 mm), thickly covered in hairs. A single plant produces up to 2000 seeds.

Medical: Flowers and stems are said to have an astringent, antiseptic, expectorant or purgative effect. None of these effects have been proven.

Online References:

References:

Older scientific or horticultural names

Knautia arvensis description by Thomas H. Kent, not updated.

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