rhubarb!!

i'm not sure i believe this.....

ABC NEWS APRIL 27

Giant rhubarb weed infests 3 states

Three southern states are on alert for a giant invasive rhubarb with 20 metre long roots which can rip up concrete.

Japanese knotweed was brought over to Australia 100 years ago as an ornamental garden plant but has infested Victoria, Tasmania and New South Wales.

The weed is hard to eradicate as herbicides take years to work and its roots are difficult to dig up.

John Weiss from the Co-operative Research Centre for Australian Weed Management says Japanese knotweed is also a big problem in the United States, New Zealand and Europe.

"In Europe they are finding they can grow... underneath roads and reach up to the other side of the road or grow through cracks in concrete, or through mortar into houses," he said.

"There are stories about them growing up drain pipes and coming out the roofs of people's houses - it is a phenomenal weed."