I walk by a house with beautiful wisteria festooning a covered walkway. It is amazing how plants can spring — did you get the pun? — back to life after the frigid -2 degrees temperature we had a little over a month ago. The shape of a wisteria vine reminds me a little of a weeping willow tree, only instead of weeping, it is crying big, fat, violet tears. According to Anne Balogh’s article “Growing Wisteria” at gardendesign.com, wisteria can completely transform a garden in just a few years, becoming a breathtaking shade cover, privacy screen or focal point. Wisteria has the greatest impact when trained to grow on pergolas, arbors and other strong overhanging supports, so the long flower clusters can hang freely, creating a stunning floral canopy. In Japan, wisteria is even trained onto massive trellises to form blooming tunnels in spring. You can also train wisteria onto wires mounted on fences or stone walls or drape them over garden benches or arched entryways. It is a very versatile vine and spectacular addition to the landscape. Let’s find out more about it.
Wisteria is a genus of flowering plants in the legume family, Fabaceae that includes ten species of woody climbing bines or twining vines that are native to China, Korea Japan and the eastern United States. Some species are popular ornamental plants. An aquatic flowering plant with the common name wisteria or “water wisteria” is in fact Hygrophiladifformis in the family Acanthaceae.
Etymology The botanist Thomas Nuttall said he named the genus Wisteria in memory of the American physician and anatomist Caspar Wistar (1761–1818). Questioned about the spelling later, Nuttall said it was for "euphony," but his biographer speculated that it may have something to do with Nuttall's friend Charles Jones Wister Sr. of Philadelphia, the grandson of the merchant John Wister. Some Philadelphia sources state that the plant is named after Wister. As the spelling is apparently deliberate, there is no justification for changing the genus name under the International Code of Botanical Nomenclature. However, some spell the plant's common name "wistaria."
Some Species
Wisteria brachybotrys or silky wisteria Wisteria brachybotrys, the silky wisteria, is a species of flowering plant in the pea family Fabaceae from Japan. Some older references believed it to be of garden origin. It is certainly very widely cultivated in its native Japan, with the white flowered cultivars more widely grown than the pale violet cultivars. It is in fact native to western parts of Honshu and throughout Shikoku and Kyushu, growing in mountain forests and woods from 100 to 900 meters. It is not at all clear why it is less popular in the west than in Japan. The Greek specific epithet brachybotrys means “short clusters.” Growing to 62 feet or more, it is a deciduous anticlockwise twining woody climber with hairy leaves to 14 inches long, each leaf comprising up to 13 leaflets. The scented flowers, borne in late spring and early summer, are pale violet or white with a yellow blotch at the base. They hang in racemes up to 5.9 inches long. They are followed by felted green seedpods containing pea-like seeds. These are reported to be toxic if ingested in quantity. Like its more famous cousins, Wiseria sinensis or Chinese wisteria and Wisteria floribunda or Japanese wisteria, it requires support when grown as an ornamental. It may be trained up a tree, a wall or a pergola. It may also be trained as a half-standard tree. It is hardy down to −4 °F but needs a sheltered position in sun or partial shade and reliably moist soil.
Wisteria floribunda or Japanese wisteria Wisteria floribunda — common name Japanese wisteria — is a species of flowering plant in the family Fabaceae, native to Japan and Korea. Growing to 30 feet, it is a woody, deciduous twining climber. It was brought from Japan to the United States in the 1830s. Since then, it has become one of the most highly romanticized flowering garden plants. It is also a common subject for bonsai, along with Wisteria sinensis or Chinese wisteria. The flowering habit of Japanese wisteria is perhaps the most spectacular of the Wisteria genus. It sports the longest flower racemes of any wisteria; they can reach nearly half a meter in length. These racemes burst into great trails of clustered white, pink, violet or blue flowers in early- to mid-spring. The flowers carry a distinctive fragrance similar to that of grapes. The early flowering time of Japanese wisteria can cause problems in temperate climates, where early frosts can destroy the coming years' flowers. It will also flower only after passing from juvenile to adult stage, a transition that may take many years just like its cousin Chinese wisteria. Japanese wisteria can grow over 30 meters long over many supports via powerful clockwise-twining stems. The foliage consists of shiny, dark green, pinnately compound leaves 10–30 cm in length. The leaves bear 9-13 oblong leaflets that are each 2–6 cm long. It also bears numerous poisonous, brown, velvety, bean-like seed pods 5–10 cm long that mature in summer and persist until winter. Japanese wisteria prefers moist soils and full sun in USDA plant hardiness zones 5-9. The plant often lives over 50 years.
Wisteria frutescens or American wisteria Wisteria frutescens, commonly known as American wisteria, is a woody, deciduous, perennial climbing vine, one of various wisterias of the family Fabaceae. It is native to the wet forests and stream banks of the southeastern United States, with a range stretching from the states of Virginia to Texas — East Texas Piney Woods — and extending southeast through Florida, also north to Iowa, Michigan and New York.
American wisteria can grow up to 15 meters long over many supports via powerful clockwise-twining stems. It produces dense clusters of blue-purple, two-lipped, flowers 3/4-inch wide on racemes 2–6 inches long in late spring to early summer. These are the smallest racemes produced by any Wisteria. Though it has never been favored in many gardens for this characteristic, many bonsai artists employ American wisteria for its manageably-sized flowers, and it is charming as a woodland flowering vine.
Wisteria sinensis or Chinese wisteria Wisteria sinensis, commonly known as the Chinese wisteria, is a species of flowering plant in the pea family, native to China, in the provinces of Guangxi, Guizhu, Hebei, Henan, Hubei, Shaanxi and Yunnan. Growing 66–98 feet tall, it is a deciduous vine. It is widely cultivated in temperate regions for its twisting stems and masses of scented flowers in hanging racemes, in spring. Wisteria sinensis was unknown in the west before 1816, when several agents of the East India Co. working in China sent cuttings back to England. Over the next several decades, the plant became — and remains — one of the quintessential ornamental vines in temperate gardens worldwide. A 200-year-old specimen, growing at Griffin’s Brewery in Chiswick, London, is often cited as the UK's oldest living wisteria plant.
It has become an invasive species in some areas of the eastern United States where the climate closely matches that of China.
Wisteria sinensis is most commonly trained along garden walls, along the exterior of buildings or over a pergola to create avenues of overhanging blossoms during bloom. It may also be trained as a freestanding tree.
Chinese wisteria is more sensitive to cold than American wisteria and Japanese wisteria. Although root hardy to USDA Zone 5 or -20 F., the vine can suffer serious dieback during such cold snaps. Moreover, the frequency of spring frosts in Zones 5 and 6 can kill latent flower buds, so that the plant might only bloom sporadically.
Planted in 1894, a one-acre specimen weighing 250 tons located in Sierra Madre, California is recognized by Guinness World Records as the world's largest blossoming plant.
Description
Wisterias climb by twining their stems around any available support. Japanese wisteria twines clockwise when viewed from above, while Chinese wisteria twines counterclockwise. This is an aid in identifying the two most common species of wisteria. They can climb as high as 66 feet above the ground and spread out 33 feet laterally.
The leaves are alternate, 15 to 35 cm long, pinnate, with 9 to 19 leaflets. The flowers are produced in pendulous racememes 10 to 80 cm long, similar to those of the genus Laburnum, but are purple, violet, pink or white. There is no yellow on the leaves. Flowering is in spring just before or as the leaves open in some Asian species and in mid to late summer in the American species and W. japonica. The flowers of some species are fragrant, most notably W. sinensis. Wisteria species are used as food plants by the larvae of some Lepidoptera species including brown-tail moth. The seeds are produced in pods similar to those of Laburnum, and like the seeds of that genus, are poisonous. All parts of the plant contain a saponin called wisterin, which is toxic if ingested, and may cause dizziness, confusion, speech problems, nausea, vomiting, stomach pains, diarrhea and collapse. There is debate over whether the concentration outside of the seeds is sufficient to cause poisoning. Wisteria seeds have caused poisoning in children and pets of many countries, producing mild to severe gastroenteritis and other effects.
Cultivation Wisteria, especially Wisteria sinensis, is very hardy and fast-growing. It can grow in fairly poor-quality soils, but prefers fertile, moist, well-drained soil. It thrives in full sun. It can be propagated via hardwood cutting, softwood cuttings or seed. However, specimens grown from seed can take decades to bloom; for this reason, gardeners usually grow plants that have been started from rooted cuttings or grafted cultivars known to flower well. Another reason for failure to bloom can be excessive fertilizer, particularly nitrogen. Wisteria has nitrogen fixing capability provided by Rhizobia bacteria in root nodules, and thus, mature plants may benefit from added potassium and phosphate, but not nitrogen. Finally, wisteria can be reluctant to bloom before it has reached maturity. Maturation may require only a few years, as in Kentucky wisteria, or nearly 20, as in Chinese wisteria. Maturation can be forced by physically abusing the main trunk, root pruning or drought stress.
Wisteria can grow into a mound when unsupported but is at its best when allowed to clamber up a tree, pergola, wall or other supporting structure. Whatever the case, the support must be very sturdy, because mature wisteria can become immensely strong with heavy wrist-thick trunks and stems. These can collapse latticework, crush thin wooden posts and even strangle large trees. Wisteria allowed to grow on houses can cause damage to gutters, downspouts and similar structures. Wisteria flowers develop in buds near the base of the previous year's growth, so pruning back side shoots to the basal few buds in early spring can enhance the visibility of the flowers. If it is desired to control the size of the plant, the side shoots can be shortened to between 20 and 40 cm long in midsummer, and back to 10 to 20 cm or 3.9 to 7.9 inches in the fall. Once the plant is a few years old, a relatively compact, free-flowering form can be achieved by pruning off the new tendrils three times during the growing season in the summer months. The flowers of some varieties are edible and can even be used to make wine. Others are said to be toxic. Careful identification by an expert is strongly recommended before consuming this or any wild plant. Chinese wisteria was brought to the United States for horticultural purposes in 1816, while Japanese wisteria was introduced around 1830. Because of its hardiness and tendency to escape cultivation, these non-native wisterias are considered invasive species in many parts of the U.S., especially the Southeast, due to their ability to overtake and choke out other native plant species.
A great wisteria tree blossoms at Ashikaga Flower Park in Ashikaga, Tochigi, Japan. The largest wisteria in Japan, it is dated to c. 1870 and covered approximately 21,400 square feet as of May 2008.
Art and symbolism Wisteria and their racemes have been widely used in Japan throughout the centuries and were a popular symbol in family crests and heraldry. One popular dance in kabuki, the “Fuji Musume” or "The Wisteria Maiden" is the sole extant dance of a series of five personifying dances, in which a maiden becomes the embodiment of the spirit of wisteria. In the West, both in building materials such as tile, as well as stained glass, wisterias have been used both in realism and stylistically in artistic works and industrial design.
How to Plant Wisteria According to Hollie Carter’s Aug. 5, 2020 article “Complete Guide to Wisteria: How to Grow and Care for Wisteria” at gardenbeast.com, wisteria loves to grow in loose, loamy soil that has plenty of nutrients and proper aeration. The soil must drain well, as wisteria does not enjoy having “wet feet.” You can choose a planting site in your yard that gets full sun throughout the day, as wisteria enjoys the direct sunlight for optimal growth. If you plant wisteria in a shady area, the plant will still grow, but it might not reach optimal heights, and you might find that the plant fails to flower appropriately during the spring and summer.
When planting your vine, makes sure that you dig out a hole that’s deep enough to cover the roots without covering the crown of the plant. Covering the crown will result in the onset of root rot, and the plant will die. Dig your hole as deep as the root ball and two to three times wider than the root ball. Space your wisteria at least 10 to 15 feet apart to avoid the plants growing into one another. Plant your wisteria in the early spring or the late fall. For those gardeners living in warmer areas, overwintering the plant is easy, and it’s the better choice to allow rapid growth in the springtime.
Choosing a Site to Plant Wisteria When choosing the best planting site for your wisteria, avoid areas with any other plants. These vines grow fast, and the size of the plant will overpower any neighboring flowers or shrubs. Make sure you avoid planting next to structures unless you want the wisteria to grow into it and cause you problems. However, there are times when planting next to structures could benefit your garden. Planting the wisteria at the base of a pergola is a fantastic idea. The vines grow in and around the pergola, and when the vines flower, it makes the structure look beautiful as the flowers leap to life and cover the structure. Mature vines get very heavy, so make sure that your structure can handle the additional weight of the plant, especially when it flowers.
Tips for Caring for Wisteria You’ll need to care for your wisteria if you want it to flower season after season. In the early springtime, apply a layer of nutrient-rich compost at the foot of the vine, and then cover it with a 2-inch layer of mulch. The mulch helps to retain the water in the soil while feeding the plant nutrients.
You’ll need to ensure that you aggressively weed around the plant when it’s young and keep weeding throughout the plant’s life cycle. Some gardeners say that feeding the plant with phosphorus aids in the plant’s flowering process, producing the biggest and most colorful flowers.
Bone meal is also another nutrient you can add to the soil in the early spring to induce flowering. Granulated fertilizer provides a slow-release into the soil that won’t damage or burn the plant.
Tips for Pruning Wisteria The secret to good flowering is pruning your wisteria. Wisteria only produces flowers on new canes, so it’s best to remove all of the old ones at the end of the growing season in the late fall. Some gardeners in warmer states can start pruning as late as mid-winter. Remove all of the dead plant matter, leaving only a few buds on each stem. For those gardeners wanting to enhance the blooming period, cut back the shoots of the plant every two weeks during the summertime. If you have a new wisteria plant, it may take it a few years to start producing flowers. In this case, it’s best to cut the plant back close to the base after planting. The following year, cut the primary stem back to three feet from the previous year’s growth.
What to Do If Wisteria Doesn’t Bloom Some gardeners might find that the wisteria doesn’t bloom. In most cases, plants fail to flower properly for the first three years, as they establish themselves in the garden. However, after the plant reaches maturity, the blooms will begin in the late spring and last throughout the summertime. Some gardeners swear by the addition of phosphate to the soil to spur flowering, while others rely on other gardening techniques to help the vines bloom. One of the more popular methods for encouraging flowering in your wisteria is to drive a shovel 8 to 10 inches into the ground, at a distance of about a foot to a foot and a half from the trunk of the vine, slicing into some of the roots. Intentional damaging the root system puts the vines into shock, and the vines start to flower as a survival response. Don’t worry about damaging the plant, as these hardy vines recover easily during the growing season. Don’t worry; it’s difficult to hurt this rampantly growing, unrestrained, often-invasive plant!
Pests and Diseases Affecting Wisteria Wisteria has its share of pests and diseases that gardeners need to be aware of during the growing season. Here’s a quick list of pests and diseases to look for on your wisteria vines:
- Dieback and leaf spot.
- Crown gall and root rot.
- Viral and fungal diseases, like mildew and mold.
- Insects like Japanese beetles, aphids, mealybugs and leaf miners.
- Scale growing on the vines.
Use organic pesticides and fungicides to remove disease from your plants and check the plants each day until they return to health.
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