Why is my polka dot plant growing like this? : r houseplants Planters Flower Pots + Garden Planters Terrain Zen Garden Plants vs. Zombies PC Computer The Spriters Resource Japanese Knotweed Facts! It might surprise you, but this fast growing, bamboo looking invasive plant is related to rhubarb! Japanese Knotweeds, originating from East Asia, belong to a family called the Polygonaceae, which are