Beautiful and Versatile Wisteria
By Lauretta Dimmick, Colorado Master GardenerSM, Colorado State University Cooperative Extension, Denver County
Do you have a fence or arbor to cover, a brick wall to soften or unsightly view to screen?
Then think vines. And not just any vine -- think wisteria.
Wisteria is one of the most enchanting of all garden plants. With its glossy, compound leaves, gnarled trunk, long strands of fragrant flowers, velvet seed pods and yellow fall color, wisteria provides garden interest for every season.
The best known wisterias are Chinese (W. sinensus) and the more cold-hardy Japanese (W. floribunda). Interestingly, the Japanese type twines in a clockwise direction and the Chinese twine counter-clockwise.
Wisteria vines can be trained into shrub or tree forms, as well as vines and even bonsai. Any arch, trellis or arbor you use for them must be sturdy. Mature wisteria can grow to 100 feet long with heavy, woody trunks and branches of great size and long life.
Wisteria plants are an investment in the future. The vines themselves are interesting -- a good thing, too -- as flowering may not begin for 10 to 15 years. The long, pea-like flowers are fragrant and range in color from white to pink, as well as the better-known blue and violet.
Hardy to USDA Zone 5, (Denver is in Zone 5), wisteria -- if planted in a protected place -- can be grown successfully in and around the metro area. Wisteria prefers full sun and, once established, is drought- tolerant. It is not fussy about soil type, actually preferring alkaline soil.
Planting a wisteria that has been grown from a cutting, or a budded or grafted plant (as opposed to a seedling), gives you a head start. From the first year, vigorous pruning is required to establish the plant's framework and to encourage earlier flowering. Wisteria is a rampant grower, so annual shortening of rambling shoots is a necessity.
Several wisteria flourish on the campus of Denver's St. Anne's Episcopal School, 2701 S. York. One very old vine twines up the east side of the Main Building and is at least 40 years old. The school's Director of Horticulture, John Navant, notes that the lavender-flowered vine probably is a Chinese wisteria. It requires very little maintenance, except for an annual pruning of the dead wood.
Although wisteria has a reputation as a fussy bloomer, Navant contends that is not really the case. He advises planting in a location with partial sun where the roots will not get "wet feet." He also recommends amending the soil at planting time using one part compost or peat moss to two parts soil.
He notes that until plants are established, they will need to be babied with timely watering both summer and winter. Then, gardeners should have good results.
Jim Klett, Colorado State University Cooperative Extension specialist in the area of landscape plants, says wisteria has been grown for 20 years at the Plant Environmental Research Center (PERC) gardens in Fort Collins. "The plant seems to be twig-and-leaf hardy," Klett says, "but--unless it's planted in a protected spot--its buds can be killed by spring frosts." For this reason, Klett adds, homeowners can become frustrated trying to grow wisteria along the Front Range, unless the plants are located in a sheltered place.
But, like the little girl with the curl in the middle of her forehead, when wisteria is good, it is very, very good. The long racemes are not only visually dazzling, they are fragrant and attract butterflies.
The Impressionist painter, Claude Monet, was so highly influenced by Japanese art that he grew Japanese wisteria to great effect on the bridge over his celebrated lily pond at Giverny.
Of moderate challenge to grow, versatile in nature and beautiful to behold, wisteria could be a glorious addition to your garden.
Photographs courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010