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Plant Profile: Knapweed (Centaurea macrocephala)

centaureamacrocephala_2Also known as hard heads, this vigorous perennial is native to the Caucasus and a relative of annual bachelor button. It has stiff stout stems that bear coarse, waxy, medium-green, lanceolate leaves with wavy margins. Orange-yellow thistle-like flowers emerge from large rust colored bud over a bloom period of two to three weeks in summer. Each flower is three to four inches across and is surrounded by brown paper-like bracts. If plants are cut to the ground after they bloom they will grow new foliage and may rebloom in the fall. Flowers are good in the vase and dry well. Plants do not need staking but may become over-vigorous in rich soil.

Type: Herbaceous perennial

Bloom: Orange- yellow thistle-like flowers three to four inches across surrounded by brown papery bracts.

Size: 5-6’ H x 2-3’ W

Light: Full sun to partial shade

Soil: Average to lean, dry to moderately moist, well-drained

Hardiness: Zones 3-7

Care: Low maintenance

Pests and Diseases: None of significance but susceptible to mildew, blight, rust, white mold, rust, mildews

Propagation: Division in spring or fall

Companion plants: Salvia ‘May Night, Cotinus ‘Grace’, Nepeta.

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