How to Grow Wisteria
The gorgeous flowering wisteria vine can lend romantic beauty to your garden. Just be aware of what type of wisteria plant you are growing and how to best manage these gorgeous deciduous vines.
Wisteria is a climbing vine, with species native to both the US and Asia. Wisteria is prized for its lovely flowering performance. As the climbing branches elongate, the vine gets heavy and creates a romantic, weeping effect.
Chinese Wisteria (Wisteria senensis)
The fragrant panicles of Chinese wisteria resemble grapes. Yet, as much of the country has come to realize, wisteria — like kudzu, honeysuckle and other flowering beauties — can be an utter nightmare. The vine has been described as invasive in at least 19 states from the Illinois to Texas, so plant with extreme care.
Wisteria sinensis is a rapid growing deciduous climber hardy to zone 5. Chinese wisteria is an aggressive plant that can potentially take over an area of the garden. So consider yourself warned: Chinese wisteria can be maintained, but will require at least a monthly pruning to control the growth.
Japanese Wisteria (Wisteria floribunda)
Capable of growing to a height of 35 feet, the woody vine Japanese wisteria has been found to be invasive from mid-Atlantic to southeastern states. Japanese wisteria can girdle and kill trees and choke out the light in a forest setting. Both the Chinese and Japanese species are extremely invasive, smothering and choking out every plant in their path, yanking down trees and creating dense thickets if left unchecked.
No doubt, these spectacular vines are coveted for their breathtakingly fragrant, pendulous blossoms in lavender, pink and white. But gardeners seeking to add one of these gorgeous vines to that newly built arbor or pergola first need to consider the bigger environmental picture — not just their own little backyard snapshot.
American Wisteria (Wisteria flutescens)
Nothing says the South quite like a front porch shrouded in a springtime veil of lavender drooping wisteria. The sugary scent of this perennial vine's flower heralds the start of a much-anticipated gardening season.
A far less invasive alternative to the Asian wisterias that is easier to control: American wisteria, Wisteria flutescens is a woody, deciduous climber native to low-lying areas of the southeastern United States. While still an aggressive plant, American wisteria grows only two-thirds as tall as its Asian cousins, and its racemes — or pendulous blossoms — are half as long, rounded and more compact — resembling bunches of grapes. And although for the most part its flowers don't emit the wonderfully sweet fragrance of the Asian species, this species is a repeat bloomer and — best of all — is valued for its manageability.
Growing American Wisteria
Wisteria plants can be purchased or seeds can be planted. However, remember that from seed, wisteria will take more than seven years before the first flowering. Many times, the seed-grown plants never flower at all. Something to think about if you want anything close to immediate gratification from your wisteria. Usually plants are grown with cuttings taken from a flowering plant. It is best to purchase the plant from a reliable nursery or while in bloom.
Spring or fall are the best times to plant wisteria and make sure you plant wisteria in full sun, otherwise you run the risk of never seeing the plant's beautiful blossoms. Wisteria loves moist, well-draining soil.
American wisteria is much slower growing, and will require minimal pruning, compared to Chinese wisteria. Wisteria performs best when pruned in spring after blooming.
Watering and Fertilizing
Established wisteria should not be fertilized and be very cautious about overwatering. Wisteria actually needs a bit of stress to form its flower buds and too much water or fertilizer will encourage leaf production rather than encourage flowering.
Wisteria Varieties to Try
American Wisteria ‘Amethyst Falls’
Sporting bright green foliage that is pest-resistant, this cultivar produces blue 4- to 6-inch racemes that are fragrant and can reach 30 feet or more. Yet it is far less vigorous than most wisterias. Hardy to zone 5, ‘Amethyst Falls’ blooms its first year — unlike its Asian cousins, which can take 10 years — but typically several weeks later than the others, allowing it to bypass the threat of a late frost. And unlike other wisterias, it offers a repeat bloom in late summer or early fall.
Deer-resistant, ‘Amethyst Falls’ is an ideal choice for fences, arbors and pergolas if given full sun to part shade. It can even be trained to grow as a free-standing tree if tied to a 6-foot stake.
Summer Cascade Wisteria
As the name suggests, this wisteria (Wisteria macrostachya ‘Betty Matthews’) bursts into flower in summer, typically June. This is a variety of a native vine known as Kentucky wisteria, which is not as aggressive as Chinese wisteria. Still, give this vine a strong support. It’s a perfect choice for a pergola over a patio. Plants grow 15 to 20 feet tall. Plant width is variable and really depends on the type of structure that supports the wisteria. Hardy in Zones 4-8.
Kentucky Wisteria 'Betty Matthews'
As the name suggests, this wisteria (Wisteria macrostachya ‘Betty Matthews’) bursts into flower in summer, typically June. This is a variety of a native vine known as Kentucky wisteria, which is not as aggressive as Chinese wisteria. Still, give this vine a strong support. It's a perfect choice for a pergola over a patio. Plants grow 15 to 20 feet tall. Plant width is variable and really depends on the type of structure that supports the wisteria. Hardy in Zones 4-8.
Wisteria contains substances — lectin and wisterin — which are poisonous for pets and people so exercise caution in planting and keep children and animals away from the plant if you intend to grow it.
Wisteria is an aggressive climber and needs very sturdy supports to grow without collapsing their trellis or pergola. Be aware that wisteria vines will grow into any crack or crevice so be very careful planting it near or onto your home. And be aware that once established, wisteria can be very difficult to remove.
A wisteria vine in Ushijima, Japan, measured 32 feet in circumference and produced more than 80,000 trusses of flowers in a 1920 report. Asian wisteria is also becoming a pest in wildlands of America, where it blooms without any help at all. So why is it that thousands of these vines growing at homes across America stubbornly refuse to bloom?
The answer lies in the history of modern Asia and the limited access to western plant hunters. With a few exceptions, both China and Japan were closed to westerners until the late 18th century. Chinese Wisteria sinensis was unknown until 1812, when a small number of English agents entered strictly for trade. In 1830, plant explorers finally introduced the Japanese species, Wisteria floribunda to the west.
In these early years only the seeds were exported from China and Japan. It is from these seeds that the first plants were grown in the west, and from that original stock many contemporary plants descend.
Many plants grown from seed can be genetically variable with any number of characteristics resulting in the offspring. Among seed-grown wisteria, some individuals may not flower for 20 years, while the average is about eight to 10 years after germination. Those first exported Asian wisteria seeds were just as variable, and so were their offspring. Before the advent of the modern American nursery, wisteria growing was a cottage industry with very little control of parentage.
The problem with seedlings is you don't know if you have a 20-year bloomer until at least 10 years have passed. This is why so many gardeners find themselves at odds with their uncooperative plants.
The most common solution is to shock the plant into bloom. This old-time process of severing roots to stress out the plant is known to kick off a survival mechanism. Thinking its life is soon to end, it makes a valiant attempt to perpetuate itself by flowering and setting seed before death. While shocking won't kill the tree or vine, it's clearly not healthy either, because it severs vital feeder roots.
Years after the early seedlings in Europe did not produce like their parents, plant hunters returned to the Far East find out why. They concluded many of the heavy, early flowering Asian plants had been started by layering, a method similar to taking a cutting that's used to propagate vines. That new plant will share the exact same heavy blooming genes of its parent.
Even a small plant can produce if carefully pruned.
This time plant collectors sent home-rooted cuttings of the best of the Chinese and Japanese plants. Gleaned from venerable old plants at historic sites, temples and ancient palaces, they were assured early and abundant bloom. These became the basis for the named cultivars that ensure you get high performing plants.