Dendromecon, commonly known as tree poppy or bush poppy, is a small genus of flowering shrubs and small trees in the poppy family Papaveraceae, order Ranunculales. The genus comprises one or two accepted species — the precise number is debated, with some botanists treating the two as a single species with subspecific variants — both native to California and the adjacent northern Baja California Peninsula.
Plants are evergreen shrubs, typically reaching 1–3 metres (rarely to 6 m in Dendromecon harfordii), with alternate, lanceolate to oval leaves 3–10 cm long that are leathery in texture. The flowers are solitary and terminal, with four satiny yellow petals 2–7 cm in diameter and numerous free stamens; both sepals and petals are shed after pollination. The fruit is a cylindrical, dehiscent capsule 5–10 cm long containing numerous smooth brown or black seeds bearing a small pale outgrowth (elaiosome).
Dendromecon rigida (bush poppy) is the widespread mainland species, found from the California Coast Ranges and foothills of the Sierra Nevada south through the Transverse and Peninsular Ranges into Baja California, growing on dry slopes and washes up to 1,800 m, particularly favouring recently burned chaparral and woodland. Dendromecon harfordii (Channel Islands tree poppy) is endemic to four of the California Channel Islands — San Clemente, Santa Catalina, Santa Cruz, and Santa Rosa — where it grows in coastal sage scrub and chaparral. It was formerly treated as D. rigida subsp. harfordii.
Both species are valued ornamentals in drought-tolerant and native plant gardens, flowering in late winter through early summer.
Etymology
The name Dendromecon derives from the Greek dendron (tree) and mekon (poppy), meaning "tree poppy" — a reference to the shrubby or small-tree habit that distinguishes it from herbaceous poppies in the same family.
Distribution
Dendromecon is native to California and the northern Baja California Peninsula. D. rigida occurs throughout the California Coast Ranges, Klamath Mountains, Cascade Range foothills, western Sierra Nevada, Transverse Ranges, and Peninsular Ranges, up to 1,800 m elevation. D. harfordii is restricted to four of the California Channel Islands (San Clemente, Santa Catalina, Santa Cruz, Santa Rosa).
Ecology
Both species are adapted to the Mediterranean-climate chaparral and woodland habitats of California. Dendromecon rigida grows on dry slopes and washes and shows a strong association with recently burned areas, making it a notable fire-follower in the chaparral. D. harfordii is confined to coastal sage scrub and chaparral on the Channel Islands.
Cultivation
Both species are cultivated as ornamental plants in native plant and drought-tolerant gardens. They perform best in full sun with fast-draining soils, though D. rigida tolerates clay if kept dry once established. D. rigida has a pH tolerance of 6–8 and a rainfall tolerance of 31–90 cm annually. Once established, plants require minimal irrigation and are valued for their long bloom season of late winter through early summer.
