I am from the Japanese islands where I am a pioneer species. By being the first to colonize inhospitable ground after volcanic eruptions, I help create new soil and make way for new plants to establish.

I was brought in by gardeners who loved my lush leaves and tall stems. People shared cuttings of me with neighbors and friends, planting me in gardens all over Europe and the United States. Once introduced, I easily escaped gardens into places I don't belong. I can grow a whole new plant from just a tiny root fragment, so I am easily spread into natural areas and streams when soil is moved from constructions and by floods.

If I get plenty of sun and moisture, I'm unstoppable! I grow so fast, so tall, and create so much shade, that no other plant can grow. Eventually, I become the only plant around. I am especially a nuisance along stream banks, where I can prevent fishermen from accessing their favorite fishing hole. I also spell big trouble for watersheds and fish by preventing native plants from growing. Healthy watersheds depend on a diversity of plants to stabilize the stream banks, prevent erosion, and filter water. I can even prevent growth of young trees that would eventually provide the shade and keep water cool for salmon. Trees also create good fish habitat once they fall into the water. It's no wonder salmon shudder when I am around.

The only real chance anyone has to control me is to catch me before I get too big. My roots go so deep that, once I am established, it is nearly impossible to dig me out. Also, if you leave just one tiny root fragment I'll be back in no time. Some people have knocked me back by injecting my stems with herbicides. Boy is that a lot of work, and even after many years of poisoning my stems, I can still come back! Your best bet is to look out for my bamboo-like stems and large heart-shaped leaves and tell someone if you find me. You should also let everyone else know about the trouble I cause and how to identify me, so more folks can be on the look-out. If you do try to dig me up, you better get all my roots and clean your boots! Otherwise, you could be spreading me around even more!