A Darwinian nightmare for humans: poison hemlock, Conium maculatum

  • Ryan Steven Heighton


Of all the invasive species known to humans, poison hemlock, Conium maculatum, is certainly among the most successful. This paper investigates why it has had such success, particularly in North America, which has only been colonized by poison hemlock for approximately 200 years. Doing a comparative assessment of peer-reviewed studies regarding the plant and its many ecological and evolutionary traits proved to be an effective way of characterizing the biogeographic nature of the species. The spread of poison hemlock has resulted in innumerable economical and environmental costs; in understanding it, preventative measures could possibly be developed. Its success is largely due to two abilities: the ability to defend itself via lethal poisons, and the ability to colonize disturbed habitats. Colonization is enhanced by seeds which do not germinate until ideal environmental conditions are met. The plant is notably allelopathic, producing chemicals that kill almost anything that feeds on it. Poison hemlock is also a fierce competitor with other plants, with almost every ideally competitive trait having been selected for over the course of its evolution.