Mimosa pigra L.

 Madagascar: Mimosa pigra is a shrubby weed that blooms and bears fruit only a few months after germination; it continues to grow and produce seeds during the dry season, from March to December.

Mimosa pigra is a perennial species that is propagated by seed. These remain enveloped in fruits divided into several uniseminate articles after maturity, and are easily spread by water, animals and tillage tools.

Under good growing conditions, a well developed individual of Mimosa pigra can produce 22,000 seeds per year.

Mimosa pigra grows in humid tropical to subtropical environments with a marked dry season (temporary watercourses, temporarily wet grasslands, etc.). Its ability to grow on various types of soil is very broad. It is found both inland in flood zones and in coastal areas, in disturbed forests, peri-urban areas and in riparian vegetation, marshes...

Mimosa pigra grows in moist places on heavy soils, embankment of streams, river beds and humid gullies in dry areas, savannah, waste places.

 
Comoros: Absent
Madagascar: Mimosa pigra grows on alluvial and hydromorhic soils temporarily flooded, rich, in sunny areas. It is a weed of semi-intensive recession crops (cowpeas, maize, cotton), of fallow and vacant lots. It is also found along the canals, in crops, roads and water bodies at low altitudes, in the alluvial plains of the Northwest and the West and the East Coast.
Mauritius: Species occasionally present in the humid degraded environments of medium altitude in the centre of the island.
Mayotte: Absent
La Reunion: Absent
West Indies: Mimosa pigra is an indigenous species. Its high seed production and tolerance of soil and climatic conditions give it a great capacity to colonise open areas. When conditions are favourable, it forms large monospecific stands. In dry areas, it is associated with Dichrostachys cinerea, which has more or less the same biological characteristics.

Origin

Mimosa pigra is native to Tropical America.
 
Worldwide distribution
 
Global distribution of Mimosa pigra from South and Central America, Southern USA, Africa and Madagascar, India, China, Southeast Asia, Indonesia, the Pacific Islands and Australia.

List of countries in the area of introduction :
- Asia: Cambodia, China (Taiwan), India, Indonesia (Java, Sumatra), Laos, Malaysia, Myanmar, Philippines, Singapore, Sri Lanka, Thailand, Vietnam.
- Africa: Benin, Congo, Djibouti, Egypt, Ethiopia, Ghana, Guinea, Kenya, Madagascar, Mauritania, Mauritius, Nigeria, Senegal, Sierra Leone, South Africa, Tanzania, Uganda, Zanzibar.
- United States (Florida, Texas, Hawaii)
- Oceania: Australia (Northern Territory, Queensland), Fiji, Papua New Guinea, Polynesia.
 

Global harmfulness

Mimosa pigra forms a dense monospecific cover in invaded wetlands, excluding the development of native plants and the survival of associated fauna. The invasion of environments by this plant causes profound changes to ecosystems.
The presence of M. pigra along irrigation systems prevents the proper flow of water. Accessibility and movement in invaded areas is particularly difficult, mainly because of the density of vegetation and the many sharp spines that make the clumps.

M. pigra is a well-known weed of extensive wetland grazing, rice fields or rice fallows, young oil palm plantations and many orchards.

Local harmfulness

Australia: Mimosa pigra was introduced into Australia (Northern territory) around 1890, in contaminated seed lots. It started to be invasive around Darwin in the 1950s and became very invasive around the 1970s. This slow rate of colonisation is thought to be due to an inability to reach environments favourable to the plant's invasive development. By 1995, the total area invaded by this plant was estimated at about 80 000 ha. These infestations have consequences for the lives of the aboriginal populations who have difficulty accessing water points and moving around the environments from which they draw part of their food.
Benin: rare and scarce.
Ivory Coast: rare but abundant when present.
Ghana: rare and scarce.
Madagascar: Mimosa pigra is a weed species common in humid areas. It is frequent and troublesome in flooded alluvial plains of northwestern Madagascar. This is a thorny shrub that not only impedes the development of cultures and driveways, but also infest pastures and fallow plots and thus require expensive cleaning work and culturing. It is particularly disturbing when farmers have only small hand tools to combat it.
Nigeria: rare and scarce.
Senegal: rare and scarce.
Sri Lanka: In Sri Lanka, this plant was discovered in 1997 and now completely covers several sections of about 30 km on the banks of the Mahaweli river.
South Africa: Mimosa pigra smothers sugar cane, crops and grasslands, leading to a reduction in land value and environmental degradation.
Thailand: Introduced in Thailand in 1947 as a green manure and cover crop, M. pigra has become very invasive along waterways and in wetlands.
USA: Introduced in Florida around 1950 as an ornamental plant or through importation of other plants. The first large-scale infestations occurred in 1985 and covered about 400 ha in 1994. M. pigra invades in particular cypress forests in this State.
Uganda: rare but abundant when present.
West Indies: Mimosa pigra grows in all crops and is very damaging when it becomes abundant. Often present on the edges of fields, it progressively colonizes plots and becomes invasive when not controlled very quickly.
 

Local control

 
Madagascar: The producers mostly use small hand tools such as angady and machetes to remove Mimosa pigra, but this method is inefficient and very costly in terms of working time.
West Indies: The management of Mimosa pigra requires the use of specific, laborious and costly weeding techniques.

Herbarium pictures ReCOLNAT: https://explore.recolnat.org/search/botanique/simplequery=Mimosa%2520pigra