Water cowbane

Pictured above: Water cowbane (Tiedemannia filiformis) by Emily Bell. Click on terms for botanical definitions. View post as a PDF.

In late summer and early fall, shallow freshwater wetlands across Florida burst to life with tall stands of Water cowbane (Tiedemannia filiformis). It is a larval host for the Eastern black swallowtail butterfly and the flowers attract a wide variety of pollinators.

Basal leaves are 2-3 feet long, terete, and form a dense basal rosette from which the flower stalks emerge and grow to 4-5 feet tall. A few reduced needle-like leaves also grow along the stem. Numerous small white flowers are arranged in compound umbels. The seed is born in a flattened, brown samara with wings along the entire edge. While evergreen in areas that lack deep freezes, it is relatively inconspicuous on the landscape when not in bloom.

Photo by Emily Bell
Photo by Emily Bell

There is a subspecies, Tiedemannia filiformis subsp. greenmanii, that is endemic to the Panhandle and considered state endangered.

Family: Apiaceae (Carrot, celery or parsley family)
Native range: Throughout Florida
To see where natural populations of Water cowbane have been vouchered, visit florida.plantatlas.usf.edu.
Hardiness zones: 8A–10B
Lifespan: Perennial
Soil: Wet organic muck
Exposure: Full sun
Growth habit: Herbaceous, erect up to 5 feet tall
Propagation: Seed
Garden tips: Water cowbane is perfect for a wetland butterfly garden.

Plants are occasionally available from nurseries that specialize in Florida native plants. Visit www.PlantRealFlorida.org to find a nursery in your area.