At the time that Europeans reached southern California, there were approximately 870 plant species growing in the Santa Monica Mountains.. Since then, however, over 200 other species have become established. The majority – the invasive weeds – were introduced by travelers and agricultural practices. Until just recently government agencies such as CalTrans and the Fire Department spent large sums of money using non-native plants near state parkland; the use of annual rye grass after fires is just one example.

Especially vexing is the problem of nurseries selling known aggressive species such as the brooms and pampas grass that invade the natural landscape – thus the name escaped exotic. As these plants enter the canyons and creep up the sides of the Santa Monica Mountains, they crowd out native plants, some of which are endangered. Unless action is taken now, our local natural plant communities will soon be altered irrevocably. Thus our chapter monitors the condition of the natural flora of the Santa Monica Mountains and works to educate the residents and all visitors as to its beauty and fragility.

We especially urge members to become familiar with the following weedy and/or invasive species, to volunteer to eradicate these plants during regularly scheduled weeding outings, and to notify park agency personnel if you find infestations of these weeds in land preserved for the protection of natural habitats.

Click Here for a pdf of the 2006 California-IPC Invasive Plant Inventory

Common Name
Latin Name
USDA Plant Database
Cal Photo Database

Curly dock
Rumex crispus
USDA Plants Database
CalPhoto

Russian thistle
Salsola kali
USDA Plants Database
CalPhoto

prickly Russian thistle
Salsola tragus
USDA Plants Database
CalPhoto

Blessed milkthistle
Silybum marianum
USDA Plants Database
CalPhoto

Spanish broom
Spartium junceum
USDA Plants Database
CalPhoto

Bigleaf periwinkle
Vinca major
USDA Plants Database
CalPhoto

Bull thistle
Cirsium vulgare
USDA Plants Database
CalPhoto

Poison hemlock
Conium maculatum
USDA Plants Database
CalPhoto

Purple pampas grass
Cortaderia jubata
USDA Plants Database
CalPhoto