Japanese wisteria, trained on an arbor near the Seattle Japanese Garden’s port village. (photo: Aurora Santiago)

Japanese wisteria (Wisteria floribunda) is a vigorous flowering vine that brings graceful spring beauty to the Seattle Japanese Garden. Planted on a substantial arbor near the port town at the Garden’s northern end, it blooms in May with many small, lightly fragrant pinkish-violet flowers, held in long, showy clusters (racemes). In Japan, it’s sometimes referred to as “the plant of two seasons” because it blooms in the weeks before spring transitions to summer.

An Ancient Genus:

Wisteria is the botanical name (and the English common name) of this ancient genus, a member of the pea family (Fabaceae) that dates from the Miocene Period (7 to 26 million years ago). Its name honors Dr. Caspar Wistar (1761-1818), a Professor of Anatomy at the University of Pennsylvania. In older references, it is sometimes spelled Wistaria.

Most species of wisteria are native to eastern Asia, with only two species originating in eastern North America. The Japanese species, Wisteria floribunda, was introduced to the U.S. in 1862. Our Garden’s vine, likely grown from seed, was planted here a century later.

Japanese wisteria and Chinese wisteria are the most popular Asian species in the West—notable for their profuse bloom, their large flower clusters, and the reliable fragrance and colors of cutting-grown plants, known as cultivars (i.e., cultivated varieties). According to Peter Valder (author of Wisterias: A Comprehensive Guide, 1995), Japanese wisteria is the more decorative plant:

“With its many-flowered racemes, it remains in bloom longer, its growth habit is more graceful, the disposition of its blossoms and foliage more elegant, and its autumn colour more effective.”

A Japanese Native:

Wisteria floribunda is a deciduous woody vine that grows vigorously, twining in a clockwise direction—unlike the counterclockwise twining of Chinese wisteria. Native to Japan, in the mountains and hills of Honshu, Shikoku and Kyushu, it grows on the edges of woodlands in light shade. Known as noda fuji, it’s been cultivated in Japan for over 1200 years. [The single word fuji refers to Wisteria species in general.] Individual plants may reach 100 years of age—and occasionally much older.

The flowers of our Garden’s Japanese wisteria. (photo: Aleks Monk, 5/24/12)

Japanese wisteria is hardy to USDA Zone 5 (minimum temperature -20 to -10 degrees Fahrenheit), and grows best in full sun—in moist, deep, fertile soils of variable pH. Plants growing in the wild show considerable variation, but the following characteristics are typical:

The compound foliage emerges pale green or bronze-green, maturing to a brighter mid-green. The silky leaves grow alternately on the stem, with each compound leaf consisting of 13-19 leaflets. Fall color is in shades of yellow.
The smooth gray bark becomes picturesque with age. Old trunks have been described as “fluted and muscle-like.”
The fragrant flowers, in shades of violet, open at the same time as the emerging leaves. Held in showy racemes, individual flowers open sequentially from the base of each raceme to its pendulous tip. The raceme lengths of plants grown from seed are variable (typically from 8 to 20 inches, and sometimes longer).
Fruits are velvety, pendulous “pea-pods,” brownish in color and about four to six inches long.

Named cultivars have been known in Japan for hundreds of years, and new selections continue to be introduced worldwide, particularly in Europe and North America. Wisteria floribunda ‘Macrobotrys’ is an ancient, well-known cultivar with very fragrant flowers and very long racemes (two to four feet long).

Tips for Choosing and Caring for Japanese Wisteria:

Because flower color, fragrance, and raceme length are unpredictable in seed-grown plants, gardeners are advised to choose Japanese wisteria cultivars, which are grown from cuttings. Moreover, seedling plants generally take 10 to 15 years to initiate bloom. Fortunately, some cultivars begin flowering much earlier, even when very young.

To encourage blooming, plant wisteria in well-drained soil in full sun, and use low-nitrogen, high-phosphorous-and-potassium fertilizer. Root-pruning an established plant (using a spade to sever the roots in a circle about 18 inches from the trunk) may also help.

With its vigorous twining branches, Japanese wisteria will eventually reach the tops of trees. In time, its trunk becomes very stout and the entire plant extremely heavy, causing damage to the structure that supports it or even to the vine itself. Training it on a very sturdy overhead structure—an arbor or pergola—is highly recommended. [In Japan, this treatment did not develop until the late 17th century; such structures are known there as fujidana.] Because of its rapid growth, it should be pruned at least three times annually, and wisteria authority Peter Valder states that Japanese wisteria requires even more careful pruning than the Chinese species.

Wisteria seeds are poisonous, especially to children and pets; flowers and foliage also contain the toxic saponin wisterin. Consumption is not recommended. In addition, Japanese and Chinese wisteria—and their hybrids—have reportedly become invasive in many eastern and southern states. To date, they are not considered invasive here in Washington.

Traditional Uses in Japan:

Before carpentry tools were invented, the tough shoots of Japanese wisteria were used to make ropes for house construction. It was traditionally planted in the gardens around Buddhist shrines and temples, and its bark was woven into cloth. Flowering stems were cut for ikebana (the ancient Japanese art of flower arranging), a usage that continues to the present.

This vigorous and very heavy vine has long been trained on arbors and pergolas, pruned and trained into a tree form, and miniaturized through the ancient art of bonsai. In some areas of Japan, it’s still possible to find old houses surrounded by wisteria hedges trained to look like swimming dragons.

Symbolism and Cultural Significance:

“Inside Kameido Tenjin Shrine,” No. 65 of *One Hundred Famous Views of Edo*. (image: Utagawa Hiroshige; Brooklyn Museum/gift of Anna Ferris.)

Japanese wisteria was mentioned—and praised for its beauty—in ancient Japanese literature, beginning with the Kojiki (translated as Records of Ancient Matters), compiled from oral traditions in 712 CE. Because it flowers in shades of purple or violet, it was originally associated only with the nobility—notably, the powerful Fujiwara clan of the Heian era (794–1192 CE). Their family crest (kamon) depicts two pendulous wisteria racemes.

With the passage of time, however, Japanese wisteria came to be associated with all classes of society, not just the nobility. Long-lived, it was seen to represent longevity, fertility, and love, becoming a favorite decorative motif that was represented in art, poetry and other aspects of Japanese culture.

By the Edo period (1603-1868 CE), many wisteria-viewing sites had been established, especially near Kyoto and Edo (now Tokyo). This tradition of wisteria viewing has endured to the present day. Like the ritual of cherry-blossom viewing, it’s a form of flower viewing (hanami). Famous sites include the Ashikaga Flower Park, the Kawachi Fuji Garden, and the Kameido Tenjin Shrine.

In the Seattle Japanese Garden:

The Seattle Japanese Garden’s arbor, with *Wisteria floribunda* in full bloom. (photo: Aurora Santiago)

The Seattle Japanese Garden’s wisteria arbor was constructed in 1960, when the Garden was created, and is located at an important juncture, where the garden style changes dramatically. Walking along the eastside path, visitors leave behind the Garden’s naturalistic southern portion and encounter its formally designed northern end. The wisteria’s imposing structure introduces the human-oriented port town, with its formalized, constructed features—the rock wall and paved stone pathway. This formal aesthetic is known as shin style, in contrast to the southern area’s naturalistic sō style.

Although the structure that supports our Garden’s Wisteria floribunda needs periodic renovation, the monumental wisteria vine endures, its trunk growing thicker with each passing year. It’s fitting that the posts and other parts are replaced with wood salvaged from the Garden or other Seattle parks, and that the gardeners and carpentry crews tend skillfully to both vine and structure. They create and maintain a feature of enduring beauty and a gift to everyone who works in, supports, and visits our Garden.

Corinne Kennedy is a Garden Guide, frequent contributor to the Seattle Japanese Garden blog, and retired garden designer.

Japanese Wisteria Brings Graceful Spring Beauty to the Seattle Japanese Garden