Plant Profile: Cow Parsnip (Heracleum maximum)

During recent walks atop Mt. Sutro, I found a fair amount of native Cow Parsnip (Heracleum maximum, syn. H. lanatum). With its large green leaves and huge stems, this local resident is an impressive sight.

What’s in a Name?

Heracleum maximum is a member of the Apiaceae (Carrot or Parsley) family. The Heracleum genus is thought to be named for Hercules due to his great strength and size, and for also being the first to use the plant for medicine. Other common names for this species are Indian celery, Indian rhubarb, and Pushki. Note that Heracleum maximum is the only member of this genus that is native to North America. In California it can be found primarily in the northern half of the state.

Characteristics

Cow Parsnip is a perennial herb. It is tall and can grow up to 7 feet. The stem is erect, hairy and hollow and each leaf is ternate (having 3 leaflets). The flowers are large white umbels (stalks spread from a common point like umbrella ribs) and its fruit is oblong (.3-.4 inches) with very fine hair. Some think the fruit has a disagreeable smell.

You’ll notice this plant for its huge leaves and large white umbel flowers – though don’t mistake it for other similar plants in the Apiaceae family, such as the highly toxic and invasive Poison Hemlock (Conium maculatum), or the Giant Hogweed (Heracleum mantegazzianum). Poison Hemlock, which is prevalent throughout much of California, has been known to cause death when its roots are eaten like wild carrots or parsnips. Giant Hogweed, which is more prevalent in the Pacific Northwest, Canada and the eastern U.S., produces a toxic sap that can cause skin irritation and blindness.

Habitat and Range

Cow Parsnip grows in variety of forested habitat types, grasslands, shrublands, meadows, alpine, and riparian zones. It generally flowers in the summer months.

Birds and butterflies are attracted to Heracleum and its numerous small white flowers, as are beneficial insects like ladybugs. It also serves as a larval host for the Anise Swallowtail butterfly.

Native American Uses

The plant’s immature roots are cooked and eaten like parsnip by North American indigenous peoples, and reportedly tastes like celery. The young, tender stalks are peeled and eaten raw by tribes including the Kashia Pomo, the Coast Miwok, and many others. As medicine, pastes of dried grated roots are applied to swollen legs to relieve swelling and also used on aching limbs and heads to relieve pain. Other uses included making a yellow dye from the roots and using the dried stems to make flutes for children.

Cultivating and Growing

In the garden, Cow Parsnip is easy to care for. Although the plants may last only a few years, they generously reseed themselves before they pass on. It prefers moist shady areas, and can grow in a variety of soils (clay, loam, or sandy soil). Because of its size and height, it is a good choice for the back of a perennial bed behind small shrubs or in the corner of a garden. It can also be used for soil stabilization and erosion control.

A Few Things to Note

The leaves and stems of Cow Parsnip contain small amounts of furocoumarins, toxins that can cause phytophotodermatitis. This means people with sensitive skin can often develop rashes when contact is followed by exposure to bright sunlight. To be on the safe side, it is best to handle this plant with gloves.

Where to Find Cow Parsnip and Other Natives for Your Garden

Cow Parsnip is available for sale at some nurseries, including the Sutro Native Plant Nursery at 476 Johnstone Drive, in San Francisco. Come visit the nursery to purchase plants or to volunteer on Wednesdays during program hours from 9:30am-12:30pm. Join us at the upcoming WINTER PLANT SALE on Saturday, February 11, 2017 from 9am-1pm. E-mail our Nursery Manager for more information or check our website for plant availability.

References

1. Cow Parsnip, Heracleum maximum. California Native Plant Society. http://calscape.org/Heracleum-maximum-(Cow-Parsnip)?srchcr=sc584cf8ab5c914

2. Heracleum lanatum (Cow Parsnip). Golden Gate National Parks Conservancy. http://www.parksconservancy.org/conservation/plants-animals/native-plant-information/cow-parsnip.html

3. Heracleum maximum. Lady Bird Johnson Plant Database. http://www.wildflower.org/plants/result.php?id_plant=HEMA80

4. Heracleum maximum. CalFlora. Plant Characteristics and Associations. http://www.calflora.org/entry/plantchar.html?crn=9546

5. Heracleum lanatum (Cow Parsnip, Indian Celery, Pushki). The Wild Garden. Hansen’s Northwest Native Database. http://www.nwplants.com/business/catalog/her_lan.html

6. Interesting Facts about Cow Parsnip. Sheryl Normandeau. Flowery Prose. May 17, 2015. https://floweryprose.com/2015/05/17/interesting-facts-about-cow-parsnip/

7. poison - hemlock. Conium maculatum L. Invasive.org. Center for Invasive Species and Ecosystem Health. University of Georgia; USDA, USFS, etal. http://www.invasive.org/browse/subinfo.cfm?sub=4365#maps

8. Giant Hogweed. National Invasive Species Information Center, USDA National Agricultural Library. https://www.invasivespeciesinfo.gov/plants/hogweed.shtml

9. Anderson, M. Kat. (2005) Tending the Wild. Native American Knowledge and Management of California’s Natural Resources. University of California Press, Pg. 268.