Tricyrtis formosana

The toad lily or Formosan Toad lily is a showy, shade-loving perennial from the lily family that has small orchid-like flowers. The Genus name "tricyrtis" is Greek. "Tri" means three, and "Kyrtos" means swelling, arched, bulging, or humped. This refers to the three sac-like nectaries at the base of the tepals (3 inner petals and 3 outer sepals). The epithet "formosana" refers to the flower that is a native of Formosa which is present-day Taiwan.

The explanation for the name "toad lily" refers to flowers being spotted like toads and having warty, sac-like bumps which are the nectaries. The genus Tricyrtis is native to China, Korea, Japan, Nepal, Taiwan, and the Philippines. The flowers are found on the edge of forests, near creek beds, and at the edge of roads. Tricyrtis genus has about 20 species but only Tricyrtis formosana and Tricyrtis hirta are common in gardens. 

The plant has an erect stem that can be as tall as 40 inches with glossy leaves. The small flowers appear at the end of the stem in clusters (cymes), and they are white with reddish-purple speckling or spots. The flower of this species is smaller than many of the other species. The plant spreads through underground rhizomes. It may be propagated by seeds, stem cuttings, or divisions. Seeds need to be collected in late fall as the capsules split open. The seeds need to be sown while still fresh and should not be covered with soil. Some species require cold stratification before they will germinate. Divisions may be done in the spring and must include an underground growth bud to be successful. Stem cuttings are easily rooted in the summer.

The plant does not perform well in deep shade and prefers light open shade. Full sun will scorch the leaves. If the plant is exposed to temperatures < 28 degrees Fahrenheit for an extended period, it will cause severe damage to the plant.

Toad lilies were introduced to United States gardens in recent years. Their use began in ornamental gardens in the mid-90s. They are deer resistant. Rabbits like to feed on new growth.

Toad lilies are best appreciated when viewed up close such as along a border or path. They complement a Shade Garden with plants such as Hosta, ferns, and astilbe. They are also a good cut flower. Various cultivars of this plant have variegated foliage, and some have purple flowers with dark spots.

Seasons of Interest:

Bloom:  Late Summer and Fall   Foliage:  Summer and Fall      Fruit:  Fall

Quick ID Hints:

• leaves are shiny, lanceolate, variegated, or non-variegated depending on the cultivar
• small orchid-like flowers about 1-inch long
• six white tepals with purple dots and a yellow throat

Insects, Diseases, and Other Plant Problems:  Slugs and snails are pests that may be attracted to this plant.  Tricyrtis floral virus, which is spread by aphids, may cause the flower color to become mottled and then change completely to purple. Anthracnose, which is a fungal disease, will cause orange spots on the stems and leaves. This can be avoided by keeping the leaves dry and watering only at the base of the plant.

VIDEO created by Andy Pulte for “Landscape Plant Identification, Taxonomy and Morphology” a plant identification course offered by the Department of Plant Sciences, University of Tennessee.