Dendromecon rigida aka Tree Poppy

Dendromecon rigida is an evergreen shrub in the poppy family, Papaveraceae. Its names include bush poppy and Californian tree poppy. It comes from California and northern Baja California in Mexico. Kew places it in the subtropical biome. This upright shrub has an uneven crown and keeps its leaves year-round. Its bright flowers stand out against blue-green leaves.

Garden height ranges from about 8–13 feet [2.5–4 metres]. The RHS description gives about 10 feet [3 metres]. Virginia Tech also records heights near 10 feet [3 metres]. Spread reaches about 3–5 feet [1–1.5 metres]. Plants take 10–20 years to reach their full size. The bark is pale gray-brown, with long, shallow cracks. It can peel into loose shreds. Slender twigs range from pale yellow-green to reddish. Their buds are small and pointed.

The simple leaves grow alternately along the stems. Sources describe their shape as oval to lanceolate. Their color ranges from gray-green to blue-green. Reported leaf lengths span about 1–4 inches. Very fine teeth line the leaf edges. Each flower has four bright yellow petals. Virginia Tech gives a width of 1–2 inches. The RHS records larger blooms, about 2–3 inches wide. The flowers have a light scent and appear in abundance. Flowering runs from late spring into early autumn, according to RHS. Virginia Tech records spring and early summer bloom. Long capsules follow the flowers and ripen from late summer into autumn. Each capsule measures 2–4 inches and splits into two valves. Inside are many small, round, black seeds.

Give this shrub full sun and soil that drains well. RHS lists both sandy and loamy soils as suitable. It accepts acid, neutral, and alkaline soil. Choose a sheltered spot facing south or west. Its RHS hardiness rating is H3. In Britain, this suits coastal areas and other mild sites. Suggested uses include coastal gardens, courtyards, and informal planting. It also fits flower beds, borders, and sites beside walls.

RHS reports few usual pest or disease problems. In early spring, remove shoots harmed by winter weather. Shorten weak shoots or those with bare sections. Prune wall-trained plants after flowering. Sow seed in spring or autumn for new plants. Other methods include summer softwood cuttings and winter root cuttings. The supplied sources give no food-use or toxicity assessment.