Tanacetum vulgare (common tansy) is a perennial herb (family Asteraceae) found in the Coastal Ranges, Cascade Range and along the north coast of California. Common tansy inhabits riparian areas, forests, and disturbed places, including urban areas, fields, and roadsides. This European native is cultivated as a landscape ornamental and as a medicinal herb. Taken in […]

Tetragonia tetragonioides (New Zealand spinach) is an annual forb (family Aizoaceae) found throughout California on sand dunes, bluffs, and the margins of coastal wetlands. As its name suggests, it is native to New Zealand. New Zealand spinach has a low-growing habit, with fleshy stems, fleshy, triangular leaves, and small yellow flowers produced leaf axils once […]

Trifolium hirtum (rose clover) is an annual forb/herb (family Fabaceae) commonly found in California, blanketing dry rangelands. Rose clover out competes indigenous clover and native grasses and can tolerate dryer soils and frost. It was intentionally introduced as grassland forage and in most rangeland systems is not considered weedy. However, in wildlands, it can out-compete […]

Ulex europaeus (gorse) is a woody leguminous shrub (family Fabaceae). In California Ulex europaeus can be found in coastal counties and the northern Sierra Nevada foothills. It invades infertile or disturbed sites, sand dunes, gravel bars, fence rows, overgrazed pastures, logged areas, and burned-over areas. Besides becoming a significant fire hazard, it can successfully out […]

Vinca major (periwinkle) is a spreading perennial vine or ground cover (family Apocynaceae) with dark green stems that contain milky latex. In California it is rapidly spreading in most coastal counties, foothill woodlands, the Central Valley, and even desert areas. Periwinkle has escaped from garden plantings, and lowers species diversity and disrupts native plant communities. […]

Verbascum thapsus (common mullein, woolly mullein) is a biennial or annual forb (family Scrophulariaceae) that occurs throughout California, but is particularly abundant in dry valleys on the eastern side of the Sierra Nevada. High population densities have been observed in moist meadows and creek drainages near Mono Lake and Owens Valley. Common mullein is a […]

Zostera japonica (=Nanozostera japonica, dwarf eelgrass) is an aquatic plant that forms dense stands in shallow, sheltered bays and estuaries. Populations of Z. japonica have been found in Humboldt County. Z. japonica often invades areas with little or no natural or human disturbance and also shows a positive relationship with disturbance. Z. japonica lives as […]

Zantedeschia aethiopica (calla lily) is a perennial (family Araceae) found along the coast of California, in the North and South Coast Ranges, and in the San Francisco Bay area. Native to South Africa, calla lily is grown as an ornamental plant, and most invading populations are found near human habitations in coastal prairies and wetlands. […]

Washingtonia robusta (Mexican fan palm) is a single-trunked palm tree (family Arecaceae) found in the San Francisco Bay area, southern Sacramento Valley and on California’s south coast. It is native to semi-arid landscapes of northwestern Mexico, including Baja California. Mexican fan palm is a common landscape ornamental that has become invasive in riparian areas, orchards […]

Festuca myuros (rat-tail fescue) is an annual grass (family Poaceae) widely distributed in California. This species is one of many introduced annual grasses that reduces habitat for native perennial grasses.