 Russian
Knapweed
Acroptilon repens
Family: Asteraceae
Description and Life Cycle
A perennial herb spreading by seeds and creeping horizontal roots. Roots are dark brown
or black, scaly, and produce stem buds that develop into leafy shoots. Stems are highly branched,
erect, 2-10 cm high, thin and stiff; young stems are covered with soft grey hairs. Stem leaves
have smooth margins and alternate on the stem; rosette leaves are oblong to lance shaped, with
irregular pinnate lobes (sometimes smooth), 5-10 cm long, and 1-2.5 cm wide. Solitary flower
heads, 15-17 mm in diameter, are surrounded by bracts 12-14 mm long; flower heads are oval,
greenish at the base with a papery, finely haired tip. Plants produce numerous tubular flowers,
10-13 mm long, pink or purple, becoming straw-coloured at maturity. Flowering occurs from July
to September. Seeds are 2-3 mm, grey or ivory in colour, surrounded by a white, deciduous fringe
of hairs (pappus) 1cm long.
 British Columbia Biological
Control Agents
References
Cranston, R., D. Ralph and B. Wikeem. 2005. Field guide to noxious and other selected weeds
of British Columbia. Gov. of BC. 94 p.
Powell, G. W., A. Sturko, B. Wikeem and P. Harris. 1994. Field guide to the biological
control of weeds in British Columbia. B.C. Min. For. Res. Prog.
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