Rhaponticum repens

(Russian Knapweed)

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Rhaponticum repens, FR 503, Uncompahgre Plateau 3034

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Rhaponticum repens, FR 503, Uncompahgre Plateau 3056

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Rhaponticum repens, FR 503, Uncompahgre Plateau 3063

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Rhaponticum repens, FR 503, Uncompahgre Plateau 3070

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Rhaponticum repens, FR 503, Uncompahgre Plateau 3082

Scientific Name Rhaponticum repens (Acropiton repens) USDA PLANTS Symbol ACRE3
Common Name Russian Knapweed, Hardheads ITIS Taxonomic Serial No. 780495
Family Asteraceae (Sunflower) SEINet
Reference
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Description Life zones and habitat: Plains to foothills (3900 to 7500 ft). Disturbed areas, roadsides.
Plant: Colony-forming perennial with multiple leafy branches, 16 to 32 inches tall; foliage covered with fine hairs.
Leaves: Basal and lower stem leaves oblong, 1-3/4 to 6 inches long, often with toothed margins and deciduous by flowering; mid and upper leaves linear to linear-lanceolate or oblong, 3/8 to 2-3/4 inches long, with a sharp-pointed tip.
Inflorescence: Solitary flower heads atop each stem branch are urn-shaped, ~1/2 inch in diameter; silvery buds open to tubular flowers of pink or purple disk florets (no rays) with that turn straw-colored at maturity; protruding white anthers.
Bloom Period: June to September.
References: "Flora of Colorado" by Jennifer Ackerfield, Colorado Department of Agriculture and Invasive Species Compendium.
BONAP Distribution Map

Map Color Key
Colorado Status:
Introduced
NOXIOUS WEED

© Tom Lebsack 2024

Banner photo: Castilleja rhexifolia and a brewing storm over the San Juan Mountains