The Centaurea Repens is native to Eurasia, and was introduced into the United States in the early 1900’s. Since that time, this invasive plant has spread to most of the United States, with the exception of the Southeast US, as shown in the distribution chart. It was believed to be introduced into the US accidentally as a seed contaminant.
This invasive species of plant grows quickly and can survive in most soil conditions found throughout the United States. Being toxic to horses, this plant is a threat in many areas and needs to be regulated. Centaurea Repens reproduces by its creeping roots and also through the distribution of its seeds, which are small oval (2-3mm long, 2mm broad, 1mm thick) seeds that have are a bit flattened with small exterior bristles. The small bristles often attach themselves to things passing by (on fur or on clothing) and once removed, find a new place to germinate.
The Centaurea Repens has black roots that spread widely up to eight feet and has erect stems that openly branch and typically grow to be between 18” – 36” tall. The leaves are alternate and clasping, the lower leaves being 2”-4” long and deeply lobed and the upper leaves are serrated and have lost the fur-like coating, but still remain small. Also produced on this plant are numerous cone shaped flowers, being pink/purple in color, with bracts below the flower that have pointed, papery sheaths.