Accidental Introduction: Poison hemlock seeds may have been unintentionally introduced to the US as a contaminant of crop seeds, animal feed, or hay imported from Europe.
Seeds could have easily 混在 with other agricultural products during transportation, leading to its establishment in the New World.
Ornamental Plant: Poison hemlock's attractive white flowers and fern-like foliage might have led to its introduction as an ornamental plant in gardens or as an escapee from cultivation.
Wool Trade: During the colonial period, wool was an important commodity traded between Europe and the Americas. Poison hemlock could have been inadvertently transported to the US entangled in wool shipments or as packing material.
Botanist's Herbarium Specimens: Botanists and naturalists of the time often collected and exchanged plant specimens for scientific research. Poison hemlock could have been introduced as part of such botanical collections.
Once introduced, the plant's prolific growth and adaptability allowed it thrive in various habitats throughout North America. Today, poison hemlock is widely distributed in many states, mostly in the eastern United States and the Pacific Northwest.