Japanese garden plans and plantings are based on centuries of practice; remains of eighth century gardens have been excavated at Nara, Japan, that follow traditional patterns.Trailing plants are used to soften lines, connect elements, line water features and provide seasonal contrasts. Japan's growing zones roughly correspond to USDA zones 6 to 11.
Japanese gardens are retreats from the outer world; the fabric and flora of their space assembled to symbolically represent the whole of nature. Clifton Olds of Bowdoin College traces formal garden design to the 11th century treatise "Sakuteiki," or "The Classic of Garden Making." Through the ages, bodies of water, lanterns, stones and bridges have become traditional elements of Japanese gardens and specific plants have assumed symbolic meanings as well.
Japanese gardens change as the year progresses and certain plants can symbolize each season. "Asagao," Japanese morning glory, and "kuzu," Kudzu vine are two of the seven herbs of autumn, according to Robert Cheetham of the Japanese Garden Research Network. Ipomoea nil and Pueraria thunbergiana are two trailing plants that become prominent in a fall garden.
Classical gardens were generally owned by nobility or religious orders and plants were typically native to the main Japanese island, semitropical Honshu or to Japan's neighbors, China and Korea. Plants in the garden reflected the classical Japanese world which was tropical, heavily forested and surrounded by mountains and sea. Yanagi, the weeping willow (Salix babylonica), provides an elegant focal point at the water's edge. The tree is native to Asian stream and river banks. The extravagant lilac-colored racemes of Wisteria floribunda Multijuga fall in great upside-down mountains of bloom; The Japanese call the plant "Fuji."
Specialized types of Japanese gardens developed as garden art was codified; the sand and stone, or Zen, garden reduces natural elements to abstract forms surrounded by a wall. The tea garden has a prominent lantern and the strolling and natural gardens contain natural waterfalls; the strolling garden features a pond. Rules do not limit creativity in design and plantings; these rely on artistic individuality. The 20- to 30-foot vine, "akebia" (Akebia quinata; chocolate vine or five-leaf akebia) could fit in any garden including a sand and stone garden -- provided it runs along its wall.
Choosing trailing plants for a Japanese-style garden in North America may present problems. Several Asian natives widely used in Japanese gardens have escaped cultivation in the U.S. and are listed as invasive or noxious weeds in many areas, particularly in the forests of the Southeastern U.S. Kudzu vine has gobbled up thousands of acres of natural areas; chocolate vine is also an aggressive grower that can cover plants and strangle them. Willow roots can crowd out other plants and Japanese climbing fern is another invasive species that aggressively displaces native plants.