Flora Fact: Keeping It Clean
Lovely Western soapberry can double as detergent.
By Karen H. Clary
If you are looking for a drought-tolerant, midsize native shade tree that flowers in early summer, attracts its fair share of bees and butterflies, turns a dazzling color in the fall and produces beautiful translucent amber-colored berries from which you can make soap, then you just might consider the Western soapberry.
Western soapberry (Sapindus saponaria var. drummondii) takes its name from the Latin sapo (soap) and indicus (Indian), alluding to the use of soap, in the form of saponins, or plant-derived soaps, by Native Americans and later on by European settlers. The Spanish name for it is jaboncillo, meaning “little soap.” The varietal name honors Thomas Drummond, Scottish naturalist, one of the earliest scientific collectors of Texas plants in the 1830s.
Soapberries are members of a mostly tropical plant family, the Sapindaceae. Western soapberry is known throughout its range (Arkansas to Arizona) for its use not only as soap but also as a treatment for fever, rheumatism and kidney problems. The inner bark has been used in home medical remedies and as an astringent. Western soapberry wood splits easily into thin strips that can be used to make frames, boxes and baskets. In the past, the wood was used for cotton baskets, crates, packsaddles and fuel. Today, soapberries are marketed as a gentle substitute for lye-based commercial soaps. Beware: Some people are allergic to soapberries.
Although saponins are found throughout the tree, they are most concentrated in the berry. This renders it a fruit to be avoided by most wildlife, except for a few mammals and birds — reportedly, cedar waxwings, bluebirds and robins, which freely devour them.
Western soapberry is a small to medium-size native tree up to 30 feet high, growing naturally along creeks, streams and river terraces throughout the state. Aransas County is home to the Texas champion: 61 feet tall, with a circumference of 108 inches.
Western soapberry is most easily identified by its grayish or tan bark and dusky green, alternate, once-pinnately compound leaves bearing up to 18 leaflets or pinnae. The small white flowers are formed on dense panicles and later produce translucent one-seeded amber-colored berries. The wood is yellow.
Soapberries flower copiously in June, a time of year when few plants flower in Texas. The perfume of the soapberry flowers attracts a host of bees, butterflies, moths and beetles.
In the fall, the tree is transformed, as Joann Merritt of Midland’s Sibley Nature Center muses, “into the glory of autumn when its green leaves turn golden yellow.” Once her grandson was so dazzled by their spectacular gold color that he ran through mounds of fallen soapberry leaves with arms outstretched, exclaiming: “I’m rich, I’m rich!”
People sometimes confuse Western soapberry with the non-native, highly invasive Chinaberry tree, which also has yellow berries and pinnately compound leaves. However, the berries of Chinaberry are opaque, never translucent, the flowers are lilac in color, and the compound leaves are twice-compound rather than once-compound.
A serious threat to Western soapberry is the recently introduced and rapidly expanding infestation of the Mexican soapberry borer (Agrilus prionurus). The soapberry borer was first reported in Travis County in 2003. Since then, it has been found in 49 additional counties. Infested soapberry trees can be easily recognized by the exposed sapwood that results when birds and squirrels chip off the bark to feed on the larvae, leaving bark chips to accumulate at the base of the tree.