September is a wonderful month for the Garden and the Gardener! An ample number of summer bloomers remain in color, yet the Garden is beginning its gradual transition into the flowers of fall. There are also a number of ‘helper’ plants that allow the transition to happen smoothly and without any noticeable incident. These are the plants that bridge the seasons, beginning their bloom in mid-summer and continuing into the fall. These plants have a multitude of colors and range from plants with dramatic displays to those that need close attention to appreciate their detail. When considering a plant that begs for up-close inspection, the Toad Lily or Tricyrtis hirta are among my favorites for their detailed blossoms and long period of bloom. Tricyrtis was originally located within the Lily Family. They were temporarily moved into the Convallariaceae or Lily of the Valley Family before that family was merged into the Asparagus Family or Asparagaceae where they presently sit. The 20-22 species are all native to Asia, stretching from the Himalayas to China and Japan, south to the Philippines and Taiwan. Tricyrtis hirta is native to Japan and the first European to see and describe this plant was Carl Peter Thunberg (1743-1828), a Swedish Naturalist and Surgeon who studied under Carl Linnaeus. At the time, it was very difficult to enter Japan in search of plants. Although Thunberg had arrived in Japan in 1775, it was not until 1776, when he was formally invited to visit the Shogun in the capitol of Edo (currently Tokyo) and to experience more of the island of Honshu. This ability to travel also allowed him to observe a much larger pallet of plants. In 1784, Thunberg wrote the book Flora Japonica and described one of the plants that he found during his travels as Uvularia hirta. The species epithet means hairy or hirsute, describing the small hairs found on the buds, stems and flowers. Unfortunately, he did not include any sketches nor bring back any specimens, so its true appearance remained a bit of a mystery. The genus name was initially penned in 1826 by the Danish surgeon and botanist Nathaniel Wallich (1786-1854), who aided in the development of the Calcutta Botanical Garden. The name comes from the Greek Tri or 3 and Kyrtos, meaning humped or bulging and was inspired by the swollen nectaries found at the base of the outer whirl of tepals (pictured on the right). Wallich was describing the Chinese and Himalayan species of Tricyrtis pilosa, which he also assumed to be the same plant that Thunberg found and described in his book. The story comes full circle when the Scottish botanist Robert Fortune (1812-1880) was in Japan during1860-62 and finally rediscovered Thunberg’s plant. He sent seeds back to the Standish nursery in Bagshot England who introduced it into commerce. In 1863 Sir William Jackson Hooker (1785-1865), a systemic botanist and Director of the Royal Botanic Garden at Kew finally provided the proper name of Tricyrtis hirta!
The common name of Toad Lily most likely stems from the purple dots on the flowers (as seen below), which exhibit a slight resemblance to the lumps on the back of a toad. It could also come from the lump-like appearance of the nectaries. Interestingly, during the early 1970’s a false story was spread under the regime of Ferdinand Marcos concerning the common name. In order to try and improve ecotourism, a story was crafted about a Filipino tribe called the Tasaday who would rub the juice of Tricyrtis on their hands and arms in order to aid in attracting and catching toads and frogs to eat. The truth was finally revealed in 1986 during a 20/20 TV investigation, but not before I repeated this story numerous times to my Herbaceous Plant class!
It is clear that the focus of this plant is all about the 1-1½” diameter flowers that begin to appear anytime from late July to mid-August and continue well into autumn. As is true of most of the species, the flowers are white or light pink with purple spots and appear like a miniature starfish when viewed from above. The flowers consist of an outer ring of sepals that are actually modified leaves and an inner ring of petals – since both the sepals and petals appear nearly identical, they are called tepals! Magnolias have a similar morphology. Several species do have yellow flowers and some even have fused tepals, creating a bell-shaped flower, so there is a degree of variation within the genus. The outer ring of tepals have a swelling at the base, which are the previously mentioned nectaries that helped in giving the genus its name. Arising from the center of the flower is the ovary that is topped by three pronged style, the tips of which split into two lobes (as seen in the image above). A style is the portion of a flower that connects the stigma, the part that receives the pollen, with the ovary. The style hovers over the anthers and has an exotic, umbrella-like appearance. The style also has hair-like glands which secrete a sticky yellow fluid that in some fashion aids in pollination. The six anthers are arranged such that they lie either in between the prongs of the style or the split lobes of the style. As the insects dive down into the flower to gain access to the nectary, their backs rub against the anthers, collecting the pollen, which is then transferred to the stigmas as the insect continues to move about this or neighboring flowers.
Not only are the flowers beautiful, but they are beautifully displayed along the stems. Tricyrtis hirta has an arching habit, growing to 2’ or taller over the course of a season. The leaves are arranged alternately along the stems, with the base of the leaf clasped about the stem. From the base of each leaf along the entire length of the stem, the flowers appear in branched clusters called cymes (as pictured on left). In the wild, the plants grow in dappled sun along woodland edges or adjacent to streams. They appreciate soils that retain moisture, but are not water logged. There are numerous cultivars available in the trade, but the selection ‘Miyazaki’ received great accolades from trials conducted at Chicago Botanic Gardens.
Another, very garden worthy species is Tricyrtis formosa, which originated in the country of Formosa, now known as Taiwan. This species is upright, growing to 3’ tall, and although the flowers are virtually identical to its cousin, they appear from the terminal leaf axils and not along the entire stem. They are stoloniferous in nature, allowing them to form large colonies within a few years. This species also requires brighter light and even a few hours of direct morning sunlight in order to thrive. One readily available selection is ‘Gilt Edge’ (picture above). Growing to 18” tall, it features attractive golden variegation along the leaf edge, extending its season of garden worthiness! Another shorter selection of this species is ‘Samurai’. Also sporting golden margins, it only grows to 1’ tall and blooms sporadically from June to frost. There are also numerous crosses that have been made between the two species, such as ‘Blue Wonder’ (pictured at left), which sports blue dots on the tepals rather than purple!
Although Tricyrtis has been in cultivation for over 150 years, it remains a much underutilized plant, well hidden from any mainstream notoriety. Despite its ease of culture, attractive foliage and form, and the longevity of bloom, gardeners feel reluctant to use the plant. Perhaps gardeners are perplexed by the common name? If this is true, they should pull up a stool – perhaps even a toadstool – to hear the stories about how this toad is truly a garden gem!