 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.
 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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