French Hydrangea: Hydrangea macrophylla - Not naturalized.
Lewis' Mock Orange, Lewis' Mockorange, Mock Orange, Wild Mockorange: Philadelphus lewisii (Synonyms: Philadelphus californicus, Philadelphus columbianus, Philadelphus confusus, Philadelphus gordonianus, Philadelphus lewisii var. californicus, Philadelphus lewisii var. gordonianus, Philadelphus lewisii var. lewisii, Philadelphus trichothecus, Philadelphus zelleri) - Erect, deciduous shrubs from 1.5-2.5 meters high. Leaves opposite, petiolate, elliptic to ovate in shape. Inflorescence of terminal racemes and solitary, axillary flowers. Calyx lobes and petals 4. Petals white, oblong, 10-20 mm long.
Common Whipplea, Modesty, Whipplevine, Yerba de Selva: Whipplea modesta - Trailing shrub, the main stem freely rooting. Leaves opposite, ovate or ovate-elliptic. Inflorescence consisting of congested panicles. Flowers white, 5-10 per cluster, calyx lobes and petals 5-6, the petals 3-4 mm long.