Xeriscape is the creation of an urban landscape in an arid region without irrigation. The joy of xeriscape is in seeing adapted plants thrive in the apparent adversity of a harsh environment. The triumph of a desert tree's health is a display of blossoms. Many xericape trees bloom abundantly in season and some bear interesting fruit or pods. Desert landscapes featuring cactus will especially benefit from shade trees, since many young cacti germinate and grow in the shade of "nurse" trees or shrubs in their natural habitat.
Get the Blues in Spring
Vitex mollis and Vitex agnus-castus bear blue flowers in late spring and early summer. Agnus-castus is a multi-trunk shrub exceeding 10 feet, native to India, southeast China and the Phillippines. From April to June, 12-inch blue flower spikes decorate its canopy, then mature to dark purple seed. Mollis is taller with less showy blossoms, but this Sonoran desert native attracts hummingbirds. Sephora secundiflora (Texas Mountain Laurel) from the Chihuahuan desert grows to 25 feet, tolerates alkaline soil and blooms a showy purplish blue 5-inch spike.
Chorisia speciosa (Silk Floss) of tropical Brazil and Argentina reaches 60 feet with a 50-foot canopy. Speciosa is deciduous. Its autumn display of pink to red flowers is lovely on bare branches, particularly at poolside. Olneya tesota (Arizona Ironwood) is a Sonoran Desert native. Individuals live up to 1,500 years and reach 30 feet. Spring clusters of pink blossoms mature to brown beanpods. Ungnadia speciosa (Mexican Buckeye), a small tree from the Chihuahuan Desert west of the Pecos River, brightens patios with pink flowers in spring.
In drought, Arizona's state tree, Parkinsonia floridum (Palo Verde), drops its leaves and photosynthesizes on branches. It booms yellow in spring and in late summer after heavy monsoons. From November to spring, 25-foot Central American Farnesiana smallii (Sweet Acacia) sets tiny flowers clustered into big yellow puffs. South American Tipuaa tipu bears orange-yellow flowers in May to July. Caesalpinia cacalaco from southern Mexico displays spikes of yellow flowers February through September. Australian Eucalpytus erythrocorys bears red buds that open to yellow flowers July to November.
Bauhinia lunarioides (Anacacho Orchid) is a small tree from a small habitat in canyons of the Anacacho mountains of west Texas and northern Mexico. In spring, Lunarioides bears white orchid-like flowers with a suggestion of pink. Sonoran Desert Lysiloma microphylla (feather bush) is densely flowered in late spring with creamy white puffs, but is also admired for fern-shaped leaves. Chitalpa tashkentensis is a hybrid of willow and catalpa that can defy monsoon winds. All summer, tashkentesis displays purplish-white lily-shaped blooms with dark purple stripes that guide pollinators.
Many Acacia have a dramatic second act of brown bean pods that add interest to the garden in autumn, but Prosopis pubescens (Screwbean Mesquite) outdoes them with clusters of helically coiled 2-inch pods. Screwbean is native throughout the desert southwest. For serious fall foliage, the leaves of Pistacia chinensis (Chinese Pistache), a 40-60 foot tree, turn gloriously orange-red. Female chinensis bear small white flowers in spring that mature to red berries.