So I thought Id have a day out to the zoo with the kids, and came across this Japanese Knotweed growing nicely in the corner of the tiger enclosure. Japanese Knotweed is harmless to humans and animals, it is not poisonous and does not cause burns, the only real problem Japanese Knotweed causes is damage to foundations, buildings and can potentially take over gardens due to its large underground rhizome growing stronger each year. Contact us today if you have any concerns that you may have Japanese Knotweed on your property.