Allium triquetrum L. is easily recognized by the triangular flowering stems and white flowers with a green stripe on the back of the tepals. It is a species from Europe that has become a weed in parts of California, Australia, and New Zealand and has naturalized in Britain. It prefers shade. Photo 1 from Mary Sue Ittner was taken at Manchester State Beach in Mendocino County, California where it has naturalized near an abandoned house. Photo 2 from Bob Rutemoeller is another naturalized population in Mendocino County. Photos 3-4 were taken by Nhu Nguyen in the Bay Area. Photo 4 shows it taking over a neglected yard. Photo 5 from Bob Rutemoeller shows a population on the Cornwall coast in the United Kingdom. Gardeners should beware of this invasive species. It is not recommended for anyone to grow this in a Mediterranean climate away from its native home in Europe.
