
Though artichoke thistle may look attractive with its bright purple flower, there is no questioning this weed’s destructive nature to the Irvine Ranch Natural Landmarks. Its aggressive root system and rapid leaf growth steals light, water and nutrients from native plants. Each plant can also produce tens of thousands of seeds per year that are blown by wind or hitchhike on animals. If left unchecked, artichoke thistle can quickly spread across a landscape, displacing native plant diversity in its path. The artichoke thistle is one of the worst threats to natural habitat within the City of Irvine Open Space Preserve’s Quail Hill.