Trees That Create Light Shade in the Southwest

Shade is welcome most of the year in the Southwest, but too much shade can limit other options. Larger-leaved trees can cast dense shade, and when their leaves drop, extracting them from spiny desert companions can be difficult. However, many ornamental plants that thrive in the Southwest actually appreciate the bright dappled shade cast by the light open canopy of desert trees. This provides ideal conditions for succulents in the genera Aloe, Aeonium, Echeveria, and Agave, as well as cacti such as flowering Echinopsis hybrids.

The best trees for underplanting are those with smaller leaves that nearly disappear when they drop. The increased winter sunlight filtering through their open branches is ideal for the understory plants, but even a light canopy can still moderate winds and provide a bit of protection from light frosts.

Here are a few favorites.

Native from New Mexico to central California and deep into Mexico, velvet mesquite (Prosopis velutina, Zones 9–11) can form extensive bosques where ground water is accessible, or it can be found as scattered individuals in smaller desert washes. A valuable wildlife tree and reliable source of nectar for bees, it has a sweet scent that wafts through the garden in spring. Pods drop in midsummer and are easy to rake up. The canopy is not dense, and most leaves drop by midwinter, allowing winter sun to keep under-plantings happy. Long-lived and deep-rooted, its strong arching branches can host native desert mistletoe (Phoradendron californicum, Zones 8–11), a favorite food of the shiny black Phainopepla bird. In Zones 9 to 11 expect a velvet mesquite tree to reach about 25 feet tall and wide and to need no irrigation once established.

Little-leaf palo verde (Parkinsonia