How did the buckthorn come here?

Buckthorn, specifically common buckthorn (Rhamnus cathartica), was introduced to North America in the early 1800s, primarily for use as a hedge plant and for erosion control. It was also valued for its medicinal properties and ability to thrive in various soil conditions. Unfortunately, it quickly spread beyond cultivation areas, becoming invasive and disrupting local ecosystems. Its rapid growth and adaptability have made it difficult to control in many regions.