Periscope
'Green cancer' stays rampant
by Cendyman Liu and Gladys Cheung
Speedy invasion of fast-growing Mikania in private farmlands and rural roadsides propels a leading local green group to plan for a large-scale campaign to clear the weed at the end of this year.
The Conservancy Association says the spread of the weed, which is often referred to as "green cancer" and "plant killer", is increasingly alarming and has worsened in private farmlands, especially abandoned ones, in recent years.
Although the government has taken some actions to deal with the weed problem, they are fragmented and confined only to government land, the group says.
Mikania, scientifically known as Mikania micrantha, grows rapidly and is dubbed "mile-a-minute". The weed can strangle trees to death by crawling along the trunks to the treetops and blocking sunlight from reaching trees underneath. It also absorbs all the nutrients from the soil.
"Eventually they (Mikania) have to be cleared. We want more people to pay physical efforts to clear them," said Lister Cheung Lai-ping, chief executive of the Conservancy Association.
Raising public awareness can help people identify and clear the weed when they spot it and stop the spread of the weed, which can also be grown on garden wastes dumped randomly, Ms Cheung said.
The weed remains rampant in the city despite a clearing campaign in the Long Valley wetland in Sheung Shui two years ago, in which 1,800 kg of Mikania was cleared mainly by students, parents, teachers and local residents.
"The weed had grown layer above layer. It was spilling out of the wetland's margins," Ms Cheung recounted the situation in the Long Valley.
Mikania, originated from Central America, was accidentally brought into Hong Kong by cargo ships in the 1850s. It only started to ravage the city since the 1990s when urban development led to a sharp rise in abandoned farmlands and increase in transport and human movements.
In the new campaign to be held in September and October,
the Conservancy Association plans to xpand the area of
clearance to private farmlands in the New Territories. The group
will seek the participation of Heung Yee Kuk, which represents
the indigenous inhabitants, and other different sectors in its
drive.
OTHER STORIES IN PERISCOPE
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Save the shades: experts
Imported plants for greening - to cure or to kill?
Invading Mikania
makes a dying tree looks
green from afar. 
A dead tree
killed by Mikania stands on a
government unleased land in
Sha Tin.
