Spanish broom (Spartium junceum) is a shrub that is native to the Mediterranean. It is known to have been in the Bay Area of California as early as 1858. In the 1930s it was planted along highways throughout California. Spanish broom thrives in natural as well as human-disturbed sites. In the foothills of Sequoia National Park it is most commonly found growing in rocky sand bars of streams and rivers.

Identification

The stems of Spanish broom are generally green, leafless, and pointed at the tips. They produce brilliant, 2.5-centimeter (1-inch) long, yellow flowers in early summer. Spanish broom can grow up to 3 meters (10 feet) tall. The leaves are small and tend to drop off early in the growing season. Spanish broom produces dry bean-like pods that are five-to-ten centimeters long.

Look-Alikes

The only native species in Sequoia and Kings Canyon National Parks that could be confused with Spanish broom is California broom (Lotus scoparius), which tends to be smaller in all regards. California broom is a common native along foothill roadways in the parks. The flowers of California broom are smaller (7-11 millimeters, or 0.3-0.4 inches long); its leaves are smaller and more persistent as well.

Big photo modified from the collection of Michael Charters; inset photo modified from the collection of Brother Alfred Brousseau, St. Mary's College.

Dense clusters of yellow flowers adorn Spanish broom in spring. A close-up view reveals pea-like flowers typical of the bean family.

Natural History

Spanish broom is able to reproduce from seed in California and it can also stump sprout. Each mature plant is capable of producing thousands of viable seeds each year. Plants in the bean family are known to produce seeds that can germinate many years after falling from the parent plant. Thus it is likely that the areas infested with Spanish broom will need to be monitored for many years after the parent populations are eradicated.

Management

Spanish broom grows in a few places around the Ash Mountain Developed Area in Sequoia National Park. It is also abundant on the flat, cobbled sandbars in the riverbed of the Middle Fork of the Kaweah River. These populations are located just downstream of the boundary of Sequoia National Park, and continue downstream for several miles through the community of Three Rivers. In 2002 park resource management personnel began manual removal of this species from the Sequoia National Park using weed wrenches. Plants that were too large to remove with a weed wrench were cut, and approved glyphosate herbicide was applied to the cut stump to kill the roots.