Development of Hybrid Baccharis Plants for Desert Landscaping

Relatively little research has been expended on developing plants for use in urban desert landscapes or “xeriscapes.” However, because of reduced availability and increased cost of water, water conservation needs, and concerns for our environment, increased awareness and demand for arid-adapted landscape plants have developed. An especially important need is for groundcover requiring little water and maintenance for arid and semi-arid regions with their limited water supply. These groundcovers are needed for a wide array of uses, such as residential landscape plantings, parks, golf courses, highway and street medians, industrial sites, and disturbed areas. The genus Baccharis (Asteraceae) consists of ≈300 species, mostly of American origin. Baccharis sarothroides Gray, commonly known as desert broom, is an erect, resinous, small-leaved, evergreen shrub, 1 to 3 m tall, and 2 to 2.5 m wide. Desert broom is extremely well adapted to the drought, cold, heat, and high soil salinity conditions of its native habitat in the Sonoran Desert and the surrounding arid regions at 300to 1700-m elevation (Kearney and Peebles, 1960). Desert broom has been recommended as a native plant useful in arid-land landscaping (Duffield and Jones, 1981; Natural Vegetation Committee, Arizona Chapter Soil Conservation Society of America, 1973; Sacamano and Jones, 1975). The species is dioecious (Fig. 1). The florets in the capitula of the pistillate plants produce a large amount of pappus, which is distributed by wind at maturity and, therefore, can create a nuisance on terraces and in pools; it also can be a potential fire hazard. This constraint has limited the acceptance of desert broom as a landscape plant. Staminate plants of desert broom, which are occasionally propagated by cuttings, are available at nurseries and are free of seed head litter. In the 1970s a staminate prostrate selec-