The first of many plants to be profiled in this series on drought tolerant plants is Chamaebatiaria millefolium, known commonly as fernbush or desert sweet. Fernbush is a shrub that is found in most western U.S. states, generally in locations that are dry and rocky with sandy or gravelly soils. However, it also occurs in sights with loam or clay loam soils, making it a plant that is not too finicky about soil types. It is found at a wide range of elevations (from 3,000 feet up to 11,000 feet) and in a wide variety of plant communities, including lodgepole pine subalpine forests, juniper-pinyon pine woodlands, mountain mahogany-oak scrublands, and sagebrush steppes. It is occasionally browsed by certain animals, but not enough to be considered an important food source. Instead, its major wildlife value is providing cover for birds, small mammals, and antelope.
Fernbush is by far one of my favorite shrubs. Its the leaves that make it so interesting. As the common name suggests, the leaves look just like little fern fronds, and considering that ferns tend to be associated with shady, moist environments, it seems strange to see a fern-like bush growing in full sun in a dry, rocky site. Alas, fernbush is not a fern, but instead a shrub with very cool leaves.
Fernbush grows to about as wide as it does high (between 1-3 meters), and depending on where it is growing it is evergreen or semi-evergreen, dropping the older leaves from the lower portions of its branches during the winter. Its bark is smooth and russet or cinnamon-colored. Flowers appear in clusters at the tips of branches in mid to late summer and are small, white or cream colored, and rose-like with five petals.
The fruit of fernbush is called a follicle and contains very small seeds, mere millimeters in size. The spent flower stalks are attractive in their own right and provide great winter interest. They can be pruned off in the spring in preparation for new flower stalks and to keep the plants looking good.
Fernbush is very drought tolerant. Once its established, it needs very little (if any) supplemental water. It is likely that the leaves of fernbush give it this trait. They are small and finely divided, as well as being hairy and resinous. Physical adaptations such as these reduce water loss through transpiration, which helps the plant use available water more efficiently. Though not very commercially available, fernbush, with its unique appearance and late summer blooms, is a great addition to waterwise gardens and landscapes.
Fun Fact: Chamaebatiaria is a monotypic genus, meaning that it is a genus consisting of only one species. In this regard, Chamaebatiaria millefolium is a true rarity.