Silverleaf, Leucophyllum frutescens, in the figwort family Scrophulariaceae, is a rounded, dense, fast-growing, evergreen, easy-to-grow shrub native to Texas, New Mexico and adjacent northern Mexican states (Coahuila, Nuevo León, and Tamaulipas). It grows in full sun in cold hardiness zones 8–10. Gardeners may want to know some of the many local common names. In English and Spanish, this drought-tolerant, attractive, long-flowering bush may be called Texas silverleaf, Texas barometer bush, ash bush, wild lilac, Texas ranger, cenizo, senisa, cenicilla, palo cenizo, hierba del cenizo, Texas rain sage or purple sage. Take your pick.
This plant’s botanical genus name is pronounced “lew co fill lum.” Ask a smartphone to say most words with an accepted pronunciation. “Leuco” means “white” and “phyllum” refers to foliage. Four Leucophyllum species are native to the southwestern U.S. and adjacent Mexican states. The genus has about 12 species.
Leucophyllum is not a sage. True sages are in the genus Salvia. For example, the annual to short-lived perennial native wildflower called Red Salvia, Texas Sage, Red Sage, Scarlet Sage and/or Tropical Sage is Salvia coccinea. The adjective “coccinea” is the female, singular form of “coccinus,” which means scarlet or dyed scarlet.
FYI: Cochineal scale insects live on pads of Opuntia cacti in tropical to subtropical regions of the Americas. The scarlet dye called cochineal, made from these dried scale insects, is used in food coloring. As early as the second century B.C.E., indigenous native peoples, including the Aztec and Maya nations, used cochineal to dye textiles and create red paint.
Some gardeners commonly call the one readily available Leucophyllum Texas silverleaf. I hope the Mexicans do not object. How about TexMex silverleaf? By any name, this fast-growing shrub has striking silver-gray leaves contrasting with small purple flowers that bloom from late spring to fall in Central Florida. As it blooms after rains, it got the name barometer bush. It is a dense but loosely branched, naturally rounded shrub that grows 5 to 8 feet tall with a 4 to 6 foot diameter. Old plants tend to sprawl, so can be pruned for shape and to induce denser branching.
Leucophyllums are desert plants that grow naturally in alkaline, gravelly, dry to slightly moist well-drained soil. Dolomitic limestone can change the pH of acidic soils. Scatter dolomite around the plant root zone after a soil test if needed. If the soil is wet or unsuitable, then plant these beauties in a well-drained raised bed. They grow naturally on rocky limestone slopes and outcrops with calcareous soils. Leucophylums tolerate heat and drought, need no supplemental irrigation once established and no fertilizer. No serious insects, pests or nutritional problems affect them. Cotton root rot may occur in soils kept too wet.
One attractive, low-maintenance shrub is readily available in privately-owned nurseries and big box outlets. The silver-gray leaves are about an inch long. Older leaves normally drop in winter and new leaves grow as soon as temperatures warm in late winter.
The best feature is the long flower season that starts as soon as the seasonal summer rains arrive in Florida. Flowering may continue into the fall. The small but showy tubular, five-lobed purple flowers grow singly from the leaf axils where leaves join the twigs. Flowers are about an inch long and attract pollinators, including bees, butterflies, moths and hummingbirds. Two-valved seed capsules develop after flowers are pollinated. Mature seeds shed naturally from mature dry capsules or may be gathered and sown in flats to grow more plants.
Leucophyllum can be used in a low privacy screen or windbreak along lot lines or to screen a pool cage. My neighbor has two Leucophylum bushes as sentries flanking a driveway entrance. Another neighbor has as a lone specimen plant in a tree ring viewable from the front door. It can be grown in large containers as a patio plant or driveway marker. The contrast between the bright flowers and silver-gray foliage is a welcome addition to any garden or water-wise xeriscape.
Jane Weber is a professional gardener and consultant. Semi-retired, she grows thousands of native plants. Contact her at email@example.com or phone 352-249-6899.