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Short Notes on Nature Singapore

25 December 2016 | Fallopia species | Knotweed |

This was a herb that I had been trying to figure out its name for quite a while but was still not certain to this day although I had narrow it down to a Fallopia species. It is a cultivated plant though I had seen it once in the wild in a deserted area, which meant that it was probably left behind by someone. It is unlikely to have naturalised since I had not yet seen a single flowering or fruiting specimen. It was not commonly cultivated here.

photo The more well-known species is Fallopia japonica (Japanese knotweed) native to Japan, China and Korea. The general appearance of the unknown herb looked similar to Japanese knotweed except for its much longer leaf stalk, at least 2 to 3 times compared to that of the Japanese knotweed. Apparently, the Japanese knotweed is considered an invasive species and had caused some serious problems in some countries, especially in the United Kingdom (UK). A 2003 publication (page 9) by the UK government put a price tag of £1.56 billion to eradicate this plant from the country. Since the cost was rather prohibitive, alternatives were explored including biological control agents. After much investigation and experiments, a promising candidate emerged in the form of a jumping plant louse (psyllid), known scientifically as Aphalara itadori. This small insect had to be brought in from Japan. A 2010 publication described the journey to reach this potential solution. In fact, this release of a foreign plant louse into the wild represented the first time that a biological control agent was used in European Union region to combat an invasive plant. Till today, the battle with the plant continues and victory has yet to be declared.

photo While researching on Follopia, I came across a Bohemian knotweed which is a hybrid between Japanese knotweed and Giant knotweed (Fallopia sachalinensis). I now suspected the unknown Follopia species seen here is most likely a hybrid but uncertain whether it is in fact a Bohemian knotweed. It seemed that Bohemian knotweed may produce viable seeds though I had not seen one done so here assuming the species seen here is indeed this knotweed. For now, I will keep its name as Bohemian knotweed (Fallopia x bohemicum).

In Singapore, there is not much wild places for any invasive plants to thrive. Even if they managed to thrive, their time is short. Sooner or later, concrete building or roads will take over the piece of land. It is a tough time to be a wild plant here. To reach the state of invasive status is a tall order, unless it can find its way to the small parcel of forested nature reserves and manage to compete with a different league of plants there.

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