Greetings to all our Village plant enthusiasts. Welcome to this weeks’ “bi-Weekly Plant of Interest”. Well it’s that time of the year again – and so how could we not include this very popular specimen of the Asteraceae family!?
Bidens formosa (Cosmos in English, Kosmos in Afrikaans and moqhoboqhobo in Sesotho), is a bushy herbaceous species that grows up to 2.5 tall. The Latin word (bi)dens means 2 – toothed, referring to the hook-like awns on the fruit, whilst formosa means beautiful. Occurs in the Eastern Cape – Gauteng in S.A. and is a native of C America and the W Indies – also occurs in several African countries.
B. formasa may be observed in stands so large that they often resemble huge and rather dazzling multi-coloured mats on road verges, fields or even across entire landscapes. The Cosmos flowers depicted here were actually photographed on a back-road in Fouriesburg, however they can be observed throughout Clarens and surrounds.
B. formosa leaves are opposite, measure approx. 100 mm X 50 mm, are deeply lobed, very fine in appearance and soft to the touch. The flowerheads are medium – large, measuring around 90 mm in diameter; occur solitary on mostly long bare stalks and whose ray florets are usually light pink, deep pink or white. The disk florets are sunflower yellow. Flowering Late Feb – May. Uses:
Makes for an attractive and in fact rather spectacular focal point for amateur and pro-photographer alike.
This particular species of the Bidens (formerly Cosmos) genus was originally introduced from the U.S.A. in the late 1890’s as a fodder source for livestock.
Cosmos is in fact not indigenous to S.A., but is rather a naturalised alien weedy species proliferating in disturbed landscapes. B. formosa is so widely distributed and occurs in such densities that elimination is practically impossible. Each plant produces hundreds of highly viable seed which are distributed with the greatest of ease. One may surmise that the presence of B. formosa could in time lead to a loss of biodiversity, however their ephemeral existence in the autumn landscape has thus far (to my knowledge) not led to any significant ecological degradation.
The attractiveness of its flowers make it one of those “must-haves” for avid botanists and keen gardeners. Easy to grow strains have been developed for this purpose. Check out https://www.mweb.co.za/gardening/PlantDetailsView.aspx?pn=Cosmos%20bipinnatus%20(=Bidens%20formosa)&type=BotanicalNames for more info.
The SANBI conservation status for B. formosa has Not Been Evaluated as Naturalized exotics are not assessed for the National Red List.