The Alien Invasion
How invasive aliens are changing the planet
Many years ago, I was writing environmental and gardening columns for an English language publication in France.
I wrote a piece on Japanese knotweed, a plant that has become a real problem in many countries.
Japanese knotweed
Introduced to Europe in the 1800s as a garden exotic, this rampant plant soon began to make a nuisance of itself. It sends its root down to a depth of three meters and spreads them horizontally as widely as seven meters.
Those roots can penetrate concrete and road surfaces and can even knock down walls. Eradication is extremely difficult as any morsel of root that is severed and left in the ground simply carries on growing.
The price of clearing ten acres of ground for the London 2014 Olympics was 70 million pounds.
The problem is not restricted to the United Kingdom. Right across Europe, this plant, which was imported purely because it looks pretty, has taken hold and is becoming a nuisance.
It has also found its way into forty-two states in America causing the World Conservation Union to declare it one of the worst invasive aliens in the world.
