Clidemia hirta

Clidemia hirta, commonly called soapbush or Koster's Curse, is a perennial shrub. It is an invasive plant species in many tropical regions of the world, creating serious damage.

Originally from the American Neotropics (Mexico to Paraguay as well as the Caribbean), it has been introduced to Australia, Southern Asia and East Africa.
It was introduced to Hawaii in the 1940s; by 1978 it had spread to over 90,000 acres (360 km2) of land on Oahu. In 1972 Koster's Curse was first spotted on the Big Island. In Sri Lanka it is quite invasive in wet zone and upcountry forests, especially invading gaps in the forest, preventing other native species from emerging.

The plant grows 1–5 metres (3 ft 3 in–16 ft 5 in) tall, depending on habitat.
The black berries are up to 8 millimetres (0.31 in) long and taste a bit like a deeply flavored blueberry. Each fruit contains more than 100 tiny (0.5 mm) seeds. It flowers and fruits all year, if conditions are moist enough. A large plant can produce more than 500 fruits in a single year. The seeds are dispersed by birds, feral pigs, other animals, and humans. Sheep will not eat the plant, and the tannin inside the fruits is poisonous to goats. The seeds can remain viable in the soil for up to 4 years.
The human edibility factor of this berry has not been fully explored. The tannin inside of the fruit is not harmful to humans and a delicious syrup may be made from the fruit. The syrup has a beautiful indigo blue color and may be used to enhance and remove the bitterness of teas such as yerba mate.

Koster's curse can form dense thickets that smother plantations, pastures and native vegetation.
Manually pulling plants out of the ground supplemented by herbicide application is an effective but temporary control method.[1] The thrips species Liothrips urichi from Trinidad is being used to biologically control C. hirta; it was first employed on Fiji in 1930 (Simmonds, 1933).
Introducing the plant to Australia can be fined with up to 60,000 (Australian) $.