POLYPODIUM GLYCYRRHIZA: Licorice Fern
Urban dwellers will catch sight of Licorice Fern clinging to Portland’s many beautiful Elm and Big-Leaf Maples (Acer macrophyllum) wherever there is a dense enough layer of moss for the roots to attach. The fronds of this fern sprout individually along the creeping rhizomes and have highly visible spore cases dotting the underside.
Really, wherever there is enough humidity for the fronds to extract the nutrients they need from the air, this fern will find a place to grow. The fern can be evergreen or summer deciduous when the air gets too dry. At the coast, licorice fern can take full sun, otherwise it likes shade to partial sun. Hardy in USDA zones 6-8.
Licorice fern is named such because of the sweet, licorice-flavored rhizomes. The Latin name for this plant is appropriately descriptive. Polypodium glycyrrhiza translates literally to ‘many-footed’ and 'sweet root’.
Many Pacific Northwest Native American tribes used the rhizomes of this plant for medicinal purposes and to sweeten foods and other medicines. It was also used in Western medicine for similar purposes; herbalists use it currently for relieving persistent skin irritants.
If you would like to introduce this lovely fern to your garden, it is important to recreate, as best as you can, the native habitat it thrives in. A woodland garden or shade garden is best. Plant it into moist, well-draining media, where it will get little to regular water.
Harvesting from the wild is illegal without a permit, but P. glycyrrhiza is available at nurseries and transplants readily with the right conditions. To find an ideal location in your garden, look for moss! This is a great indicator of the necessary conditions for Licorice fern to thrive. This fern also spreads by setting spores, although sporelings are slow to develop.
If you would like to read more:
Familiar Friends – Northwest Plants by Rhoda Whittlesey
Gardening with Native Plants of the Pacific Northwest by Arthur R. Kruckebery
Plants of the Pacific Northwest Coast by Jim Pojar & Andy MacKinnon
Morgan Hayes and Peggy Acott
Common: Licorice Fern
Origin: Temperate west coast rainforests and low elevations from northern California to southern Alaska.
Characteristics: 5-12” fronds hang gracefully from the limbs and bark of big-leaf maples and other deciduous trees in the wild. The lower third of each frond is generally bare stalk, the upper two-thirds bearing small and decreasing-in-size pinnae narrowing to a point at the tip.
Licorice fern can be found covering rocks, on logs, carpeting forest floors and dangling above on tree limbs.
Culture: This fern is epiphytic, so it needs a moist atmosphere. Licorice fern grows best at low elevations, preferring mossy areas on rocks, stumps and logs, trees and slopes. This fern can be evergreen or summer deciduous when the air gets too dry.
At the coast, licorice fern can take full sun, otherwise it likes shade to partial sun.
Hardy in USDA zones 6-8.
Pests & Diseases: None noted. Its demise in the garden is usually due to a lack of sufficient water or of trying to grow it only in soil, without addition of moss.