Foxglove (Digitalis purpurea) is a showy biennial weed common in mid-elevation meadows and streams of Sequoia and Kings Canyon National Parks. It is native to Europe and is commonly cultivated for its highly ornamental flowers. In our parks, it actively displaces native species from fragile wetland environments.

Identification

Foxglove is a biennial; it produces a healthy rosette of oblong leaves its first year. These leaves are 10 to 30 centimeters (4-12 inches) long, with irregularly toothed margins. During its second year, a foxglove plant produces a great number of large showy flowers. The elongated flowering stems can attain heights of nearly two meters (6 feet), but are more commonly about 1 meter (3 feet) tall. The flowers are large, pendulous, tubular, and variously colored.

Look-Alikes

A foxglove plant is unmistakable when in full bloom. A vegetative foxglove rosette can vaguely resemble some native wetland species. Positive identification of foxglove is best determined when there are mature flowering individuals present.

Photo by Jo-Ann Ordano, © California Academy of Sciences

The highly distinctive foxglove flowers are borne along the upper part of a single, soaring stem (not visible here).

Natural History

One mature foxglove plant can produce thousands of seeds. Most foxglove plants are biennial, but some individuals may live for more than two years. All parts of the foxglove plant are toxic to humans and livestock. Some varieties are cultivated for production of the heart medicine digitalis.

Management

Foxglove is localized to a few sites in Sequoia and Kings Canyon National Parks, but in these sites it is abundant. It is actively invading riparian and meadow areas in Grant Grove, Giant Forest, and Lodgepole.

Volunteer efforts to eradicate foxglove began in 1999. Plants were hand-pulled in Grant Grove and Giant Forest. With the addition of a 2-person weed crew in 2001, additional populations in riparian areas of Grant Grove were worked more thoroughly. The abundance of foxglove in the private inholding of Wilsonia provides a continual source of propagules to riparian areas of the Sequoia Creek watershed. Creative education and involvement of the Wilsonia community is a priority.

The NPS management goal for this species is containment and removal from high-priority locations, such as riparian areas, meadows, and non-developed areas. Because foxglove seed is long-lived in the soil, local eradication could take 10 years or longer.