A common yet special herb that offers cardiovascular and immune support.* Botanical Name: Polygonum cuspidatum. Part Used: Dried root. About Japanese Knotweed Tincture: This common herb made its way to the United States from Japan, China, and Korea, where it has established itself heartily in the landscape across the country. Japanese Knotweed is an important herb for people who live in areas of high tick concentration to familiarize themselves with. Our tincture utilizes the fresh root of the plant, but the young shoots are also a delicious and nourishing wild edible. Japanese Knotweed root supports the immune system and the nervous system. Research shows that the root of this plant may contain properties that benefit a healthy cardiovascular system, including support to the physical tissues of this beautiful, heart-centered system.