Introduced to the US as a garden plant this species has become very invasive. Growing to heights of six feet a single plant can produce a colony 6′ in diameter. Flowers are reddish purple and clustered tightly. When the seeds are mature in the Fall the leaves often turn bright red. A single plant will produce 3 million seeds annually.
The plant can also reproduce from fragmentation.
Infestations result in elimination of all native species and clogging of waterways. Once established physical and chemical control is difficult and expensive.
If you observe this plant growing please take the time to report its location.