Crataegus monogyna (English hawthorn) is a deciduous shrub or small tree (family Rosaceae) found in California along the north and central coast and in the North Coast Ranges. English hawthorn was introduced to California as a landscape ornamental. It has escaped cultivation, growing in moist soil in riparian areas, woodlands and grasslands. At about 10 […]

Cotula coronopifolia (brassbuttons) is a perennial herb (family Asteraceae) found along the coast of California, in the Central Valley and the South Coast Ranges. Brassbuttons prefers moist habitat, including salt and freshwater marshes, wetlands, and vernal pools. It most commonly invades disturbed sites, but can spread into undisturbed sites as well. This South African native […]

Cotoneaster pannosus (silverleaf Cotoneaster) is an evergreen shrub (family Rosaceae) found along the central and north coast of California, as well as in the northern South Coast Ranges and the Transverse Ranges. Silverleaf Cotoneaster has small, leathery, ovate leaves with hairy white undersides, white flowers arranged in clusters, and red fruits. It was introduced from […]

Cotoneaster lacteus (Parney’s Cotoneaster) is an evergreen shrub (family Rosaceae) found along the central and north coast of California. Parney’s Cotoneaster, which has white flowers and red fruits, was introduced from China as an ornamental plant, and has escaped cultivation. It is found in disturbed places, especially near residential sites, as well as undisturbed coastal […]

Cotoneaster franchetii (orange Cotoneaster) is an evergreen shrub (family Rosaceae) found in the northwest and central west regions of California. Orange Cotoneaster, which has pink flowers and orange fruits, was introduced from China in 1854 as an ornamental plant, and has escaped cultivation. It is found in disturbed places, especially near residential sites, as well […]

Cortaderia selloana (pampasgrass) is a large perennial grass (family Poaceae) found along the coast of California, and in the Coast Ranges, Central Valley, Western Transverse Ranges, and Mojave Desert. Pampasgrass favors dunes, bluffs, coastal shrublands and marshes, inland riparian areas, and disturbed areas. It was introduced as an ornamental plant and for erosion control. Each […]

Conium maculatum (poison-hemlock) is a biennial forb (family Apiaceae). Poison-hemlock has spread throughout California in areas below 5,000 feet (1,500 m) elevation, excluding the Great Basin and Desert provinces and is commonly found in dense patches along roadsides and fields. It also thrives in meadows and pastures and is occasionally found in riparian forests and […]

Conicosia pugioniformis (narrowleaf iceplant) is a succulent perennial (family Aizoaceae) found on dunes, beaches, scrub and grassland along the central coast of California, especially in Santa Barbara and San Luis Obispo counties. Narrowleaf iceplant does not form mats like other invasive iceplants (i.e., Carpobrotus edulis or C. chilensis) so its impacts are less severe. However, […]

Cirsium vulgare (bull thistle) is a perennial or biennial forb (family Asteraceae) Bull thistle is widespread in California and is most common in coastal grasslands, along edges of fresh and brackish marshes, and in meadows and mesic forest openings in the mountains below 7,000 feet (2,120 m). It is most troublesome in recently or repeatedly […]

Cirsium arvense (Canada thistle) is a perennial (family Asteraceae) found scattered throughout California, except in the Sonoran and Mojave Deserts and the southern Sierra Nevada. Canada thistle forms dense patches which may crowd out native vegetation. This clump-forming plant reproduces by seed and vegetatively from its extensive root system. Control is difficult because root fragments […]