Christiane Holmquist's Top Plant Recommendation: Favorite Trees for Southern California.
Pineapple Guava - Acca (Feijoa) sellowiana
Pineapple Guava. A well grown, well behaved tall shrub 18-25 ft by equal spread that can be trained into a multi-turnked small tree, espalier, screen or hedge . Its silvery green foliage persists on it throughout the year. It provides delicious fruit and white flowers tinged on purple inside in spring that are not only pretty but make a tasty sweet addition to fruit salads and drinks. The plant is drought tolerant but needs regular water for better fruiting.
Strawberry Tree - Arbutus 'Marina'
Strawberry Tree. The size is perfect, even for a smaller garden. Attractive in all seasons, with shiny dark green foliage, rosy-pink flowers and edible fruit. Laces out beautifully to reveal the gorgeous peeling bark; very tolerant of "almost any garden situation". Can reach 20-30 ft with equal spread.
Caribbean Copper Plant - Euphorbia cotinifolia 'Atropurpurea'
Caribbean Copper Plant. Graceful and mysterious, an upright multi-trunked shrub with dark burgundy foliage that can be trained into a small tree. Deciduous in Zones 20 + 23. Drought tolerant but can also handle regular garden water. Beautiful contrast to flowering perennials and grasses. It tolerates light frost and stays generally under 20 ft but can reach 30' over time. (People with allergies should protect themselves against the sap which can cause rashes with some.) Great with blue or magenta flowers (Princess Flower, Rock Purslane or Lavender), ornamental grasses, red or yellow perennials.
Catalina Ironwood Tree - Lyonothamnus floribundus asplenifolius
Fernleaf Catalina Ironwood. Fast growing, it is an evergreen slender tree with interesting reddish-brown peeling bark, attractive dark green foliage and showy clusters of flowers. It makes a good vertical accent plant. It is hardy for most locations in our county (to 23 F), and quite drought tolerant.
Black Locust Tree - Robinia pseudoacacia
Black Locust. A deciduous tree that looks like a giant Wisteria tree in spring, fragrant too. Fast growing to 40-70' tall and 30-50' wide, open habit, thorny branches. Tolerates heat, drought and poor soil. (Root suckers are less of a problem with some regular watering). Flowers best with some winter chill. For modern selections, cultivars and smaller hybrids with interesting foliage or more colorful flowers, see R. 'Frisia' , R. x ambigua 'Idaho' or 'Purple Robe'.
Chitalpa Tree - x Chitalpa tashkentensis 'Pink Dawn'
Deciduous tree that grows quickly to 20 ft. Showy light-pink trumpet clusters from late spring to fall, no seeds. Drought tolerant once established, needs full sun, loves heat and good air circulation and tolerates a wide range of soils and garden conditions.