Invasive Species
Invasive Species in Los Angeles
The City of Los Angeles is interested in knowing where important invasive plants are found. Invasive plants did not evolve in Los Angeles; they were introduced by human activity from elsewhere in the world, and they harm the native biodiversity that sustains Angelenos. Understanding where these plants are found is crucial to tracking the spread of invasives and reducing the negative effects they have on Los Angeles' ecosystems. The invasive plant species cards below highlight some key invasives that are particularly harmful and easily recognizable. They can be found potentially anywhere, from highly urban areas to large natural open spaces, so your observations of invasive plants will be essential for the City and local researchers.
The invasive species cards below indicate where you are likely to spot certain species.
You can also learn more with L.A. Sanitation and Environment's comprehensive guide, Biodiversity Indicator Species Booklet, which can be found on the L.A. Sanitation's Biodiversity webpage. Your observations of invasive species will be extremely important to City staff and local scientists in reducing their negative impact on our local ecosystems.
How many invasive species can you observe this October?
Giant Reed
Arundo donax
Giant reeds are tall, bamboo-like grass that invade areas near rivers, growing quickly and removing native plants.
Saltcedar
Tamarix ramosissima
Saltcedar invades riverbanks and desert areas, increasing soil salinity and harming native plants.
Castor Bean
Ricinus communis
Castor beans have large, palm-like leaves and spiky, toxic seeds that can harm ecosystems.
Yellow Starthistle
Centaurea solstitialis
Yellow starthistle has spiny, yellow flowers and invades grasslands and open areas, reducing habitat quality.
Black Mustard
Brassica nigra
Black mustard is tall, yellow-flowered, rapidly takes over disturbed areas, and is particularly problematic for encouraging wildfire.
Tree-of-Heaven
Ailanthus altissima
Tree-of-heaven has compound leaves, damages nearby infrastructure with its strong roots, and releases a chemical into the soil that is toxic to native plants.
Crimson Fountain Grass
Pennisetum setaceum
Crimson fountain grass has long, fluffy, and bristly flower spikes, often used in landscaping but can invade all over Los Angeles.
French Broom
Genista monspessulana
The french broom is a shrub with bright yellow flowers that can replace native plants with dense areas of just this plant.
Tree Tobacco
Nicotiana glauca
Tree tobacco has bluish-green leaves and tubular yellow flowers and is found throughout parks and along roads, replacing native plants.
Pin-Tailed Whydah
Vidua macroura
This bird is a parasite, laying its eggs in the nests of native bird species.
Red Swamp Crayfish
Procambarus clarkii
Found in freshwater habitats, this crayfish disrupts food webs by eating native insects.
Red-Eared Slider
Trachemys scripta elegans
These turtles are often kept as pets, but they can seriously damage ecosystems by outcompeting native reptiles and introducing parasites.
American Bullfrog
Lithobates catesbeianus
These frogs have huge appetites that will eat and outcompete Los Angeles' native species. It can also introduce fungus that threatens native amphibians.
