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.

Name

The epitheton hirta means "scrubby" in Latin. "Koster's curse" is a commonly used name in places where the plant grows as a noxious weed, such as Hawai'i. Koster was the man who between 1880 and 1886 accidentally introduced seeds of C. hirta to Fiji in coffee nursery stock, where its problematic nature was first noticed around 1920 (Paine, 1934; Simmonds, 1937). Originally only known as "the curse" for the damage it did to coconut plantations, its vernacular name became a model after which those of other invasive plants were patterned, such as Ellington's Curse on Fiji, McConnel's curse in Australia, Curse of India in East Africa or Burbank's Folly in the Pacific Northwest.

Biology

The plant grows from one up to five meters high, depending on habitat.

The black berries are up to 8 mm 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.

Distribution

Originally from the neotropical region (southern United States to Brazil), it has been introduced to Australia, Southern Asia and East Africa.

It was introduced to Hawai'i 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.

Biological control

Koster's curse can form dense thickets that smother plantations, pastures and native vegetation.

To destroy the plant pull it up by its roots and hang it upside down so that the roots dry and can not reattach themselves to the ground. Be careful not to spread the berries.

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) $.

Synonyms

Taxonomic synonyms for C. hirta include:

• Clidemia benthamiana
• Clidemia cognata
• Clidemia crenata
• Clidemia elegans
• Clidemia leptocada
• Clidemia pauciflora
• Dancera hirta
• Leandra fimbriata
• Melastoma anhaga
• Melastoma aristatum
• Melastoma elegans
• Melastoma rustica
• Staphidium elegans
• Staphidium hostmanii

References

• Paine, R.W. (1934): The control of Koster's curse (Clidemia hirta) on Taveuni. Fiji Agricultural Journal 7(1): 10-21.
• Simmonds, H. W. (1933): Biological control of Clidemia hirta. Fiji Agricultural Journal, 6(2): 32–33.
• Simmonds, H. W. (1937): The biological control of the weed Clidemia hirta commonly known in Fiji as 'the curse'. Fiji Agricultural Journal, 8(3): 37–39.

External links

• Images of C. hirta
• New World Fruits Database
• John K. Francis: Clidemia hirta (PDF file)