Milfoil

Achillea millefolium L.

Family: Asteraceae.

Names:

Milfoil

Other Names:

Yarrow

Summary:

Aromatic, hairy to almost woolly, rigid, erect, rhizomatous, perennial herb with feathery leaves and flat-topped clusters of white to red flowers on stems to 40 cm tall.

Description:

Cotyledons:

Two.

Leaves:

Alternate.
Stipules -
Petiole -
Blade - 40-150 mm long. Narrow in outline. Finely divided 2-3 times. No small pinnae between larger ones. Furry hairs. End lobes parallel sided with fine sharp transparent tip. Leaf rachis narrow and not winged or toothed between the primary segments.

Stems:

Flower stem - Erect, woolly hairs, striped.
Underground rhizomes.

Flower head:

Forms a dense, broad corymb of flowers at the ends of the stems.

Flowers:

Oval cluster, 3.5-4 mm long.
5 white to red petalled ray florets surrounding white or cream disc florets in centre. Disc florets between membranous finely tapered scales.
Bracts - Oblong and membranous with thickened midribs.
Ovary -
Petals - 3 lobed

Seeds:

Small and somewhat flattened. No pappus. No ribs.

Roots:

Underground stems (rhizomes or stolons).

Key Characters:

Biology:

Life cycle:

Perennial herb with underground stems (stolons).

Physiology:

Reproduction:

By seed.

Flowering times:

October to April in SA.

Seed Biology and Germination:

Vegetative Propagules:

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Origin and History:

Europe and Asia.

Distribution:

ACT, NSW, SA, TAS, VIC.

Courtesy Australia's Virtual Herbarium.

Habitats:

Damp disturbed areas. Gardens, lawns and vegetables.

Climate:

Soil:

Plant Associations:

Significance:

Naturalised garden escape.

Beneficial:

Ornamental. Medicinal herb.

Detrimental:

Troublesome weed of lawns. Weed of vegetables, roadsides and wastelands.

Toxicity:

Not recorded as toxic.

Legislation:

None.

Management and Control:

Thresholds:

Eradication strategies:

Herbicide resistance:

Biological Control:

Related plants:

Tansyleaf Milfoil (Achillea distans ssp. tanacetifolia) has a courser habit, winged leaf rachis and often with small pointed lobes between larger leaf segments.
Woolly Yarrow (Achillea tomentosa).

Plants of similar appearance:

Cotula, Jo jo.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P81. Photo.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P878. Diagram.

Burbidge, N.T. and Gray, M. (1970). Flora of the Australian Capital Territory. (Australian National University Press, Canberra). P369. Diagram

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #10.2.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.