Hopbush (Dodonaea viscosa) is in the soapberry family (Sapindaceae) and is known by about 50 different common names. Hopbush is related to the Western Soapberry tree (see article). You can see many specimens on the grounds of the Arizona-Sonora Desert Museum.
ASDM describes this plant as “…a multi-trunked, evergreen shrub typically 5 to 7 feet (1.5-2.1 m) tall, occasionally to 10 feet (3 m), with bright green foliage. Inconspicuous clusters of small, greenish flowers are followed by showy winged fruits resembling hops on female plants. Flowering and fruiting are variable but mostly in summer and fall.” See some good photos here (where it is called Hopseed bush). See also a great photo from Arizona State University of many bushes in the Superstition Mountains northeast of Phoenix at about 3,000 elevation.
The fruit or seed pods contain just three or four seeds. These winged-pods start out green, then with age, turn a creamy color, followed by a red tinge and finally turn brown when dried out. The fruit is toxic because it contains saponin a compound that tastes like soap.
ASDM: “In the Sonoran Desert region, Hopbush occurs from central Arizona to Sonora and Baja California, from 2000 to 5000 feet (600-1500 m) elevation, always at the upper margin of the desert and often in acidic soils. The same species occurs in warm regions worldwide, even Australia. Exceedingly few plant species have such a wide distribution.”
Hopbush fruit has been used as a substitute for real hops when brewing beer in Australia. True hops, Humulus lupulus, is in an unrelated family.
The Seri people of the southwest used the plant medicinally for a variety of purposes (but sources are not specific). It was also used to stimulate lactation in mothers, as a dysentery treatment, to cure digestive system disorders, skin problems and rheumatism in Africa and Asia. In New Guinea, people use it as incense for funerals.
The wood is extremely tough and durable. In New Zealand, where it is the heaviest of any native wood, the Maori have traditionally used it for making weapons, carved walking staves, axe-handles, and weights on drill shafts. Hopbush is also used by the people from the western part of the island of New Guinea, Southeast Asia, West Africa and Brazil for house building and as firewood. Its leaves may also be used as plasters for wounds. (Source)
“The bark is sometimes used in poultices for swellings and headaches and is added to baths. The leaves have pain-killing, wound healing and diaphoretic (sweat-promoting) qualities as well as being astringent and useful for skin rashes, toothache and sore throats. A decoction or infusion can be made from them and the liquid applied to affected areas of the skin.” (Source)
The U.S. Department of Agriculture says:
The fibrous spreading root system, rapid growth, and spreading canopy make D. viscosa an effective soil stabilizer which is particularly useful in controlling gully and coastal dune erosion. It is drought tolerant and has the ability to withstand wildfires. D. viscosa shrubs are somewhat shade tolerant and suitable for riparian and restoration projects. They are also very wind hardy and useful as an in-field windbreak system.
D. viscosa is an aesthetically pleasing plant. It has lush green foliage and deep red capsules that make it pleasing to the eye. D. viscosa may be used as a hedge, specimen plant, or maybe a small patio tree. It is ideal for xeriscape gardens.