Invasive Plant Species: Onionweed
Onionweed (Asphodelus fistulosus), a member of the Lily family, is a species that prefers wet washes or riparian areas in the Park. It is a pretty plant and was grown as an ornamental prior to it being listed on the Federal Noxious Weed list. Areas in
How did it get here?
Onionweed was new to the Park in 2006. It was most likely planted as an ornamental by homesteaders in the Rincon Creek area. Seeds were spread into the Park during the 2006 flood event.
What is the threat?
Onionweed takes moisture, minerals, and nutrients from the soil, denying them to native plant species. The thick mats of leaves provide dense shade, blocking sunlight, and discouraging germination of native plant seeds.
Management goals and strategies
Onionweed is easily removed by hand. During the fall, we visit the infested sites and remove any new plants we find. We are constantly on the look out for new infestations.
We would like to work with our upstream neighbors and private land owners along Rincon Creek to remove it from their property. We believe that, with the help of our park neighbors, onionweed can be eliminated from the Park.