Springtime in the woodlands of eastern North America begins slowly and ends with a crescendo of blossoms that carpet the forest floor in May. Many of the earliest wildflowers in this succession of bloom can be effective and adaptable additions to the home shade garden. One such wildflower is our native twinleaf, Jeffersonia diphylla. Its flowers are fragile and fleeting, lasting only a couple of days, but they are a sure sign of spring. The delicate floral beauty and intriguing leaf shape of Jeffersonia make it a desirable plant for gardeners who want to try something new in their shade gardens.
Jeffersonia diphylla is a clump-forming woodland perennial that is hardy in Zones 5-7. Its white, daisy-like flowers are one inch in diameter and cup-shaped. They are borne individually atop eight-inch, wiry, leafless stems. The flowers are followed by unusual pear-shaped seed pods with hinged lids. As the pod stalks elongate, the leaf stems also grow, and the plant ultimately reaches a height of eighteen inches. Twinleaf derives its common name from the shape of its deeply divided leaves. Each leaf is about five inches wide by six inches long and is divided into two nearly separate halves, like a mirror image. It resembles a butterfly that flutters atop its slender stem. When the leaves first emerge from the soil they are a unique, rich coppery red. The copper color slowly fades, and the foliage takes on a chalky, blue-green hue. Twinleaf makes a significant contribution as a ground cover in the woodland and home garden, adding bold texture and unusual form.
The only other species of twinleaf in the world occurs in the woodlands of eastern Asia. This species, Jeffersonia dubia, is similar in many respects to its American counterpart. Its flowers, however, last up to two weeks and are a remarkable soft lavender-blue. The plants are about six inches in bloom, with the leaf stalks ultimately growing to twelve inches. The leaves of J. dubia are not as deeply divided as our native twinleaf and, although lovely, have a less pronounced effect as a ground cover.
Horticulturalist William Bartram named Jeffersonia in honor of his friend, Thomas Jefferson. The bloom time of Jeffersonia roughly coincides with the President's April 13tthbirthday. Although it is considered poisonous, twinleaf has been used throughout history as a medicine. Native Americans used it in poultices and infusions to treat a variety of ailments. Traditional Chinese medicine used it as a treatment for the stomach and fevers.
Jeffersonia is notoriously difficult to propagate by division since it grows from a very dense crown. Happily, it grows easily from seed. I grow both species in my gardens and have found that J. dubia reseeds itself more energetically than our native twinleaf. I move some of the tiny seedlings to new locations or grow them on in nursery beds. J. diphylla spreads less readily and new seedlings take years to produce flowers, but, for me, the eventual blooms are more momentous due to the wait.
As is the case with most woodland wildflowers, Jeffersonia is most successful in home garden situations that mimic its native habitat: deciduous woodlands with rich, moist, calciferous soils. In the home garden, it requires shade, but adapts very well to drier conditions once established and will thrive in soils within the normal range of acidity. No garden should be without the delicate beauty of its spring blossoms and the presence of its unusual and aptly named leaves. You can purchase twinleaf locally from Garden in the Woods in Framingham and from online sources such as Mason Hollow Nursery, www.masonhollow.com.
By Joan Butler