Why Is It A Weed?
What are its impacts?
Mother of Millions and hybrid Mother of Millions were included in the list of 71 species that were nominated by state and territory governments for assessment as Weeds of National Significance (WONS). Following an assessment process, Mother of Millions and hybrid Mother of Millions were not included as one of the 20 WONS. However, it remains a weed of potential national significance, and is highly toxic to stock and humans.
Native ecosystems: Both species are also regarded as significant environmental weeds in Queensland and New South Wales. They are well adapted to dry environments, are able to survive droughts, and can form very large infestations in grasslands and open woodlands in inland regions (Navie & Adkins 2007).
Mother of Millions is currently of most concern in southern and central Queensland, and in 2002 was ranked as the third most important environmental weed in south-eastern Queensland (Batianoff & Butler 2002). It is actively managed by community groups in Queensland and is listed as a priority environmental weed in eight Natural Resource Management regions in eastern Australia (Navie & Adkins 2007). In inland central Queensland, near Dingo, Mother of Millions is competing with and replacing the native herbs that make up the diet of the endangered Nail-tailed Wallaby (Onychogalea fraenata). In inland southern Queensland, it is one of four invasive plant species that is impacting on the endangered Isis Tamarind (Alectryon ramiflorus). It is also very invasive in sandy coastal sites, such as on foredunes and coastal islands. In one study it was found to be one of the twelve most invasive ornamental species on the foredunes of the Sunshine Coast (Hannan-Jones & Playford 2002).
Hybrid Mother of Millions is less common and widespread at present, and is currently of most concern in south-eastern Queensland. However, it was still recently ranked among the top 30 most invasive plants in this region. In New South Wales it is becoming increasingly common, particularly in the north-east of the state, and is also naturalised around the opal fields near Lightning Ridge (Navie & Adkins 2007).
Agriculture: Mother of Millions and hybrid Mother of Millions are very poisonous to livestock and humans. Cattle deaths resulting from ingestion of these species are quite common, particularly in south-eastern Queensland (Hannan-Jones & Playford 2002). These species commonly invade rangelands and native pastures, replacing useful grasses and legumes, and significantly reducing the productivity of pastoral areas.
NSW DPI (2019) staet that Mother of millions is toxic when ingested by livestock, it is also poisonous to humans and household pets. Ingestion of the toxins can be cumulative and livestock eating small amounts, several times within a few days may suffer poisoning. Eating about 5 kg of mother of millions would kill an adult cow. Where the plants are thick, this amount would grow in a square metre. Poisoning generally occurs when the plants are flowering – between May and October. Livestock are at a greater risk of poisoning if they have been moved to a new paddock, there is a feed shortage or during droving because they are more likely to eat the plant. If livestock have eaten a large amount of plant, they may die suddenly of heart failure. If they have eaten smaller amounts over several days, they may develop diarrhoea (sometimes bloody), drool saliva, dribble urine and then die of heart failure. Some affected livestock will recover slowly if small amounts of plant material have been eaten and their hearts are not badly damaged. Poisoned stock must be treated within 24 hours of consuming the plant. After this period heart function is severely disturbed and stock may be too badly affected to survive. If you suspect livestock could have mother of millions poisoning, consult a vet immediately.
Urban areas: Mother of millions can become weedy in the drier gardens and little carried for gardens. These plants can subsequently spread and jump the garden fence in to other areas. It is also toxic to humans and household pets with dogs being particularly susceptible. It is unlikely that humans or pets would eat enough plant material to become poisoned. However, because mother of millions can be found in many gardens, the likelihood of human or pet poisoning is increased (NSW DPI 2019).
How does it spread?
Mother of Millions reproduces by seed and by tiny plantlets that are produced at the tips of its succulent leaves. Hybrid Mother of Millions produces plantlets along the edges of its leaves and on the branches of its old flower clusters. Dislodged leaves and broken leaf parts of both plants can also take root and give rise to new plants (Navie & Adkins 2007).
These species are commonly spread in dumped garden waste. Their very fine seeds are probably wind and water dispersed and their leaves and plantlets may also be dislodged and spread about by animals, vehicles, machinery and slashers (Navie & Adkins 2007). Plant parts are also washed downstream during floods, and this is probably the most significant method of large-scale dispersal throughout catchments in inland areas (Cant 2007).
What is its history in Australia?
Both of these plants were deliberately introduced and cultivated as garden ornamentals. They quickly escaped cultivation, primarily when excess or unwanted garden plants were dumped in bushland and gullies. Due to their succulent nature, they survived and often spread down local watercourses. The first herbarium specimen of naturalised Mother of Millions was collected in 1947, and hybrid Mother of Millions was first collected in 1965. However, Mother of Millions certainly became naturalised at some time prior to this. For example, the first reported outbreak in Chinchilla Shire in Queensland occurred in 1940. A survey of Queensland in 1980 estimated that Mother of Millions infested an area of approximately 10 000 hectares (Hannan-Jones & Playford 2002).