Senecio jacobaea (tansy ragwort) is a noxious perennial, biennial, or sometimes annual weed (family Asteraceae) native to northern Africa, Asia, and Europe, that that occurs mostly in northern California. Plants are ruffled rosettes when young and erect when mature, growing up to  4′ . Leaves are twice pinnately compound and dark green. Flower heads have […]

Sesbania punicea (red Sesbania, scarlet Wisteria) is a deciduous shrub or small tree (family Fabaceae), up to 4 meters tall. Sesbania punicea is mostly found in riparian areas in the Central Valley, forming clusters so thick that access to the river becomes difficult to impossible. It displaces native plants used by wildlife and contributes to […]

Silybum marianum (blessed milk thistle) is a winter annual or biennial with prickly leaves (family Asteraceae). It is widely spread throughout California in overgrazed pastures and along fencelines and other disturbed areas. Blessed milk thistle produces tall, dense stands that outcompete native species.

Ranunculus repens (creeping buttercup) is a spreading perennial forb/herb (family Ranunculaceae), found in many coastal areas of California. It can sometimes form large monocultures, especially in moist areas.

Genista monosperma (bridal veil broom) is an escaped ornamental plant in the family Fabaceae. Although it is currently invasive in only one population in San Diego County, Cal-IPC lists it as an alert species due to its invasiveness in other areas with climates similar to California. In six years, this one infestation spread in size […]

Ricinus communis (castor bean) is an semi-woody large shrub (family Euphorbiaceae). Native to the southeastern Mediterranean, eastern Africa, and India, it has escaped cultivation and established outside of its historic range to become a noxious weed in many mild climates, including in southern and central California. It has a shrubby habit but can reach the […]

Robinia pseudoacacia (black locust) is a deciduous tree (family Fabaceae) that grows to 100 feet tall. Historically planted as a landscape tree, black locust has escaped cultivation and become invasive in California and elsewhere. It can grow on a wide range of sites, but grows best on rich, moist, limestone-derived soils. It does not do […]

Rubus armeniacus (Himalayan blackberry), formerly known as Rubus discolor, is a sprawling, essentially evergreen, glandless, robust shrub (family Rosaceae). Rubus armeniacus occurs in California in the coast ranges, Central Valley, and Sierra Nevada. This weed is a strong competitor. It rapidly displaces native plant species and thickets to produce such a dense canopy that the […]

Rumex acetosella (red sorrel, sheep sorrel) is a perennial forb/herb (family Polygonaceae). In California, sheep sorrel occurs in a freshwater marsh community and is common in annual grasslands, montane meadows and perennial bunchgrass communities.

Raphanus sativus (wild radish) is an annual or occasionally a perennial (family Brassicaceae) that frequently invades grasslands and open/disturbed areas, including roadsides in California. Wild radish may also be found in wetland areas. Wild radishes are capable of excluding native plant species and are, on rare occasion, toxic to livestock.