August Tree-of-the-Month: Soapberry

Sapindus saponaria

There are surprisingly large numbers of trees growing successfully in the Santa Barbara community that have origins in much wetter tropical and subtropical climates than ours, with the Soapberry being a good example.  This small- to medium-sized semi-deciduous tree is quite happy in our Mediterranean climate and has proven to be a very drought tolerant and sustainable tree. 

Soapberry is an attractive round-headed tree that can grow to a height and spread of 20- to 30-feet.  Its crown is covered with pinnately-compound leaves growing up to 15-inches-long. On each leaf there are 3 to 6 pairs of leaflets, which are 2 to 6-inches-long and 1 to 2-inches-wide. The leaflets are glossy green above and dull green and hairy beneath, bear smooth margins, and develop swollen bases at their stem attachments.  In the fall, the leaves often turn a bright yellow, providing an attractive fall color before dropping off.

In late spring into summer, the crown is filled with panicles (10- to 12-inches-long) of small (1/8-inch wide) creamy-white to greenish-white flowers.  The tree is “monoecious”, meaning there are both male flowers and female flowers on each tree.  

After pollination, the fruit that forms can be more colorful and attractive than the flowers.  The clusters of round (¾-inch-diameter) bright yellow-orange berries can be easily seen since they extend outside the foliage.  As the berries age, they turn maroon-brown and resemble a bunch of grapes; in the fall as they ripen, they turn a darker brown.  After the leaves have fallen, some berries remain attached all winter long, adding interesting decoration to the tree.  

The bark is smooth and light gray when young – and becomes fissured and scaly with age.

Soapberry is native to South Florida, to the West Indies, and to tropical and subtropical areas of Central America, Mexico and South America.  It naturally occurs in well-drained sandy and rocky soils.  It is listed as being hardy in USDA Zone 9, which means that it can tolerate winter temperatures as low as 20-degrees F. 

Soapberry is in the Sapindaceae plant family, which is so named to reflect the high saponin content in many of its species.  The Soapberry’s botanical name is Sapindus saponaria.  The genus name, Sapindus, comes from the Latin words “sapo”, meaning soap, combined with “indus“, in reference to the West Indies.  In addition to the common name, “Soapberry”, it also goes by many other common names including, “Florida Soapberry”, “Soap Nut”, “Soap Tree”, and “Winged Soapberry”.

In its native areas, it has been used for many purposes.  Most notably –  and the reason it is named Soapberry – is for its use by indigenous people as a soap. The fruits are mashed in water to produce a soapy lather, which is then is used for washing laundry, for personal hygiene, and for household cleaning.  

While the seeds are basically inedible, they are used as beads in crafts, rosaries, and buttons.  They can be crushed and used as insecticides.  Hunting tribes have used them in large quantities to paralyze fish.  The wood is utilized as a construction material.

Soapberry grows in full sun to partial shade.  It has no serious insect or disease problems and is generally low maintenance.  It is easy to propagate from seed, provided the seed is scarified or lightly cracked and then soaked for 24 hours before planting.  

Soapberry makes a lovely small shade tree, street tree, or patio tree.  Due to its adaptability to growing conditions, it has been widely used as an ornamental tree in areas with mild climates such as ours.

Mature specimens of the Soapberry can be seen in several places in our community as street trees, often mixed with other tree species: on the 300, 600 and 700 blocks of Alisos Street; on the 1100 block of Del Sol Avenue; on the 600 block of West De La Guerra; and, on the 700 block of West Victoria Street.               

Tree-of-the-Month articles are sponsored by Santa Barbara Beautiful, whose many missions include the increase of public awareness and appreciation of Santa Barbara’s many outstanding trees and, in a long-time partnership with the City Parks & Recreation Department, the funding and planting of trees along the City’s streets.

Those who wish to honor a special someone can do so with an attractive commemorative marker that will be installed at the base of an existing street tree in the City of Santa Barbara.  Because Santa Barbara Beautiful has participated in the planting to date of over 13,000 street trees, there are plenty of trees from which to choose!  Application forms are available on the Santa Barbara Beautiful website, www.sbbeautiful.org.