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Invasive Species

The City of Los Angeles is particularly interested in knowing where certain biodiversity invasive species are found.

The City of Los Angeles is interested in knowing where important invasive plants are found. Invasive plants did not evolve within Los Angeles, having been 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 track the spread of invasives and reduce the negative effect 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 space, 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 LA Sanitation and Environment's comprehensive guide, Biodiversity Indicator Species Booklet, which can found on their website. Your observations of invasive species will be extremely important to City staff and local scientists to reduce the negative impact they have on our local ecosystems.

How many invasive species can you observe this October?


giant reed on a hillsideScott Loarie

Giant Reed

Arundo donax

Giant reeds are tall, bamboo-like grass that invade areas near rivers, growing quickly and removing native plants.

iNaturalist

saltcedar growing among palm leavesIrene

Saltcedar

Tamarix ramosissima

Saltcedar invades riverbanks and desert areas, increasing soil salinity and harming native plants.

iNaturalist

castor bean plant with full leavesQuentin Groom

Castor Bean

Ricinus communis

Castor beans have large, palm-like leaves and spiky, toxic seeds that can harm ecosystems.

iNaturalist

yellow starthistle grows in the wildKallum McDonald

Yellow Starthistle

Centaurea solstitialis

Yellow starthistle has spiny, yellow flowers and invades grasslands and open areas, reducing habitat quality.

iNaturalist

black mustard grows among other plantsJesse Rorabaugh

Black Mustard

Brassica nigra

Black mustard is tall, yellow-flowered, rapidly takes over disturbed areas, and is particularly problematic for encouraging wildfire.

iNaturalist

tree of heaven photoBranislav Tej

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.

iNaturalist

crimson fountain grass grows near lake and mountainsAna Nuño

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.

iNaturalist

french broom with yellow flowersPeter F

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.

iNaturalist

close-up of tree tobacco yellow flowersAna Nuño

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.

iNaturalist

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