Quick Facts

Quick facts

• Originally from Europe and North Africa, Stinking Mayweed (Anthemis cotula) is an upright, much-branched, foul-smelling annual herb
• Herb to about 600 mm similar in appearance to Chamomile with its dissected leaves and white and yellow daisy flowers.
• It is a weed of disturbed sites, pasture, crops, gardens, roadsides and wasteland.
• The plant has a pungent disagreeable smell and it taints animal products such as meat and milk.
• May cause poisoning in poultry, dogs, cats and horses.
• May cause contact dermatitis in certain people.
• It is spread by seed and can be controlled by physical removal, cultivation and chemicals.

What Does It Look Like?

What is it?

Stinking Mayweed (Anthemis cotula) is an upright, bushy annual daisy growing up to 60 cm high. It has a very strong foul (malodorous) odour when crushed, touched or brushed against, has an acrid unpleasant taste. Its upright stems are striate (striped with parallel, longitudinal lines or ridges), sparsely hirsute (bearing coarse, rough, longish hairs) to glabrescent (loosing all hairs to become hairless and smooth), and are densely branched. The leaves are alternate on the stem, without a leaf stalk (sessile), and are pinnatisect, (finely and deeply divided to the midrib / vein into very narrow segments). Leaves in outline are ovate (egg-shaped in outline with the widest part at the base) to obovate  (egg-shaped in outline with the widest part nearer the tip of the leaf) , 15–65 mm long, 10–30 mm wide.

The daisy-like flower-heads are solitary or in small leafy clusters, on peduncles (main flower stalk) 60–150 mm long. Flower-heads are surrounded by involucral bracts ( a group of leaf-like structures surrounding the base of a flowerhead) that is narrow-lanceolate (lance-shaped), 3–4 mm long, glabrous (smooth without hairs) to cobwebbed. Flowers-heads 15-30 mm across with a yellow centre (disc florets), and 10-15 white 'petals' (ray florets). Each of the 'petal' is 5-14 mm long with three small teeth at its tip. The centre of the flower-heads (capitula) is made up of numerous tiny 3 mm long yellow flowers (ray florets) and is somewhat raised and cone-shaped (conical). Each flower produces a seed with many seeds produced on a flower-head.

The fruits or 'seeds' (cypselas) are reddish brown, 1–2 mm long, with about 10 ribs with miniature wart-like outgrowth. Seeds are without a pappus (hairy parachute) (Cooke 1986; Auld & Medd 1992; Hardin 1992; Jeanes 1999; Parsons & Cuthbertson 2001; Navie 2004; Richardson et al. 2006). Flowers Oct–Apr.

For further information and assistance with identification of Stinking Mayweed, contact the herbarium in your state or territory.

Flower colour

White and yellow

Growth form (weed type/habit)

Herb

Where it currently grows? Preferred habitat

Stinking Mayweed occurs in humid to semi-arid temperate regions. Often in disturbed sites, it is a weed of gardens, pasture, annual crops, roadsides and wasteland, often in or near cultivation. It is also found in grasslands, on river flats and floodplains. Although Stinking Mayweed may be found in a variety of conditions, including a wide range of soils, its preferred habitats generally have heavy soils (mainly clay loams and heavy clays) that have been disturbed, such as poorly managed or degraded pastures, farmyards, holding paddocks and other cleared areas (Curtis 1963; Cooke 1986; Auld & Medd 1992; Hardin 1992; Jeanes 1999; Parsons & Cuthbertson 2001; Richardson et al. 2006).

Are there similar species?

Stinking Mayweed may be confused with other daisy species with finely divided (fern-like) leaves and daisy flower-heads with white 'petals' and a yellow centre (i.e. yellow centre made up of numerous disc flowers surrounded by white ray florets), but it is distinguished by having a strong foul odour when the plants are crushed or brushed against.

Corn Chamomile (Anthemis arvensis), also known as Field Chamomile, differs in its ascending or decumbent growth habit (i.e. reclining to semi-erect habit where the stems are spreading horizontally before becoming upright or the branches are only turned up at the ends), its smoothly ribbed achenes (fruits) and in being hardly aromatic when crushed (Auld & Medd 1992; Hardin 1992; Jeanes 1999; Richardson et al. 2006).

Dyer's Chamomile (Anthemis tinctoria), also known as Golden Marguerite, is an upright perennial herb also with a strong odour but it has yellow flower-heads that fade to cream (Richardson et al. 2006).

Common Chamomile (Chamaemelum nobile) is a prostrate or ascending aromatic perennial herb with creeping underground stems, and is used as a medicinal herb and for lawns (Richardson et al. 2006).

Why Is It A Weed?

What are its impacts?

Stinking Mayweed is an important weed of cereal crops in Europe, Argentina, New Zealand and parts of the United States. In Australia it is a weed of agriculture, waste areas, roadsides and as garden weed (Parsons & Cuthbertson 2001).

Agriculture: it invades cultivated areas, pastures and paddocks (Parsons & Cuthbertson 2001). Can be a weed in annual crops and may contaminate seed crops, occasionally an invasive species in pastures. The plant has a strong, offensive, sickly odour and bitter taste. Where livestock have grazed this weed, it may taint animal products like milk, butter and meat (Auld & Medd 1992; Parsons & Cuthbertson 2001).  Stinking Mayweed is poisonous to poultry (Auld & Medd 1992; Richardson et al. 2006), and may cause poisoning in horses.

Native ecosystems: Not known to invade intact vegetation, but will invade disturbed areas or degraded sites.

Urban areas: In urban areas it is a garden weed (Parsons & Cuthbertson 2001), and a weed of disturbed and waste places. It has been implicated in cases of human dermatitis – prolonged contact with the flower-heads and the fruit is reputed to cause dermatitis and blister the skin (Auld & Medd 1992; Parsons & Cuthbertson 2001). May cause poisoning in dogs and cats.

How does it spread?

Stinking Mayweed reproduces and spreads by seed, which is dispersed as a contaminant in hay, chaff and pasture seeds. It can also be spread in mud sticking to hooves, wool, footwear, clothing, tyres, vehicles and machinery of all kinds (Parsons & Cuthbertson 2001). Ensure that all machinery, equipment and vehicles coming onto your property are not contaminated.

What is its history in Australia?

Stinking Mayweed was probably introduced to Australia with, or shortly after, the arrival of the first European colonists (Parsons & Cuthbertson 2001). The first herbarium record was made in Adelaide in 1848, the second from Victoria in January 1870, and the third from New South Wales in March 1870 (AVH 2021).

How To Manage It?

Best practice management

Integrated weed management plans are required to prevent the spread of Stinking Mayweed. Control measures should aim for the eradication of existing populations and to prevent the establishment of new infestations. Integrated management plans and control measures for Stinking Mayweed are outlined by DPIPWE Tasmania (2019). Preventative control measures are the most desirable and effective means of weed management. Planning and implementation of a property management plan is required with an integrated control program aimed at eradicating all existing populations and preventing future infestations of Stinking Mayweed. Such a plan should be based on integrated weed management principles and include an inventory of Stinking Mayweed infestations in the area to which the plan relates, well-defined objectives, practicable control actions, follow-up actions, a realistic timeline and a budget, as a minimum.

Chemical control: There are various herbicides available for effective chemical treatments, see  DPIPWE Tasmania (2019); Parsons & Cuthbertson( 2001); and Tamar Valley Weed Strategy (2015). Control is often difficult because there are a range of plants at different growth stages. Spot spray for smaller patches and boom spray for larger areas. Please see the Australian Pesticides and Veterinary Medicines Authority for further chemical information http://www.apvma.gov.au .

Non-chemical control: Physical control: Individual plants and small infestations can be hoed or grubbed out using hand tools, ideally while at the seedling stage.

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

Seeds germinate at any time of the year provided moisture is available, resulting in infestations of plants of various ages. The two main periods of germination are autumn and spring. Flowering occurs October-April and then the plants die. Some seeds are dormant when shed, and may remain viable for up to 25 years when buried (Jeanes 1999; Parsons & Cuthbertson 2001).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, SA, TAS, VIC, WA

What areas within states and territories is it found?

In Australia, Stinking Mayweed occurs from south-eastern Queensland (in the Moreton District where it is uncommon), through eastern New South Wales, mainly Tableland and coastal areas but occasionally on the Western Slopes and Plains) to parts of Victoria (mainly eastern areas) and Tasmania where it is widely distributed, especially in the north and north-west, with populations in the south around Hobart.

There are small infestations in the Adelaide Hills of South Australia.

In Western Australia populations are found in the Donnybrook region of south-western Western Australia (AVH 2021; Cooke 1986; Stanley & Ross 1986; Hardin 1992; Jeanes 1999; Parsons & Cuthbertson 2001; Western Australian Herbarium 2007; ). It may not be truly naturalised in Western Australia where it has only been occasionally collected (Hussey et al. 1997; Western Australian Herbarium 2007).

Where does it originate?

Stinking Mayweed is native to the majority of Europe and North Africa (POWO 2019), especially around the mediterannean region (Parsons & Cuthbertson 2001).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

TAS

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Anthemis cotula

Other scientific names (synonyms)?

Maruta foetida Gray

Does it have other known common name(s)?

Dillweed, Dog Daisy,  Dog's Camomile, Dog Fennel, Dog-fennel, Dog's Fennel, Foetid Chamomile, Fetid Camomile, Mather, Mayweed, Stinking Chamomile, Wild Chamomile, Hog's Fennel, Dog-finkle, Morgan, Dog-daisy, Pig-sty Daisy, Maise, Chigger-weed, Balders