March-April 2019

Pendant purple chains of wisteria blossoms on romantic sweeping vines put garden lovers around the world in a springtime swoon.

They conjure delightful impressions of floral cascades as seen on Monet’s arching bridge at Giverny or draped across English cottages.

The Japanese hold a major festival, Fuji Matsuri, in wisteria’s honor at shrines every spring where admirers flock to breathe in its perfume and absorb its perennial spectacular beauty.

After wisteria blooms, long bean-like velvety pods remain, offering another interest and texture.

After wisteria blooms, long bean-like velvety pods remain, offering another interest and texture.

On grand old homes of the American South, wisteria vines adorn verandas in voluptuous style, enveloping them with profuse clusters of pea-shaped lavender flowers, creating a dreaminess that is hard to resist. “Well, resist!” cries a home gardener who is overwhelmed by attempts to tame the Asiatic stranglers that have, like Kudzu, jumped their bounds, crushed their pergolas, or consumed the gutters of the porches they once outlined so gracefully.

Fortunately, Americans have come to the rescue. Natives Wisteria frutescens (American wisteria) and Wisteria macrostachya (Kentucky wisteria) are much better behaved than their invasive cousins and sport many desirable attributes that make growing this classic charmer environmentally responsible again.

American wisteria is a deciduous, woody climber that grows more slowly than foreign types and so is much more manageable. The non-aggressive vine will not form a heavy trunk, so it can be grown on fences and railings without worry that it will destroy the wooden structure. Best of all, the American varieties of wisteria rebloom in late summer or early fall, a huge asset.

A type of W. frutescens that has gained widespread popularity is “Amethyst Falls,” which blooms its first year, unlike Chinese (W. sinensis) and Japanese (W. floribunda) varieties that take seven years to flower. American wisteria has bright green foliage and is deer resistant. The pale blue racemes are shorter, about 4-6 inches, and bloom after the plant has leafed out, unlike the Chinese variety that produces its chains of bloom before any leaf growth. The American vine’s flower clusters, bunched and tidy, make gorgeous displays as seen on picket fences and arbors in Colonial Williamsburg, and have the advantage of needing little pruning.

Kentucky wisteria is native to the south-central U.S. and is noted for its superb winter hardiness, producing flowers in zones USDA 3-4. It blooms later than the Asian types, so there is less chance of it getting damaged by a late frost. The racemes of this variety are longer than those of American wisteria — up to 12 inches — so the dramatic displays of yesterday are possible today.

American wisteria stays in bounds and will  not devour this arbor.

American wisteria stays in bounds and will
not devour this arbor.

Flowers are followed by velvety, bean-like seed pods, hanging in masses that are themselves decorative, forming interesting displays that last into winter. The cultivar “Blue Moon” is highly desirable as it may bloom up to three times in a growing season and its foot-long, captivating blooms exude the lovely fragrance for which the Far Eastern varieties are known. Since this vine grows 15-25 feet, it does require a sturdy structure that will be able to support its weight at maturity, so plan accordingly. It is particularly effective grown above a patio onto an overhead frame, supporting the dazzling clusters and, later, providing a canopy of leafy shade.

To ensure bloom, plant wisteria in full sun and purchase a named variety of vine; experts recommend buying a grafted vine, not one grown from seed. To be sure you know what the flowers will look like, consider buying the vine while it is in flower, then plant in soil enriched with humus, and water regularly during the first summer.

Japanese wisteria displays incredibly long, luxurious and fragrant racemes during the Wisteria Festival in Tokyo.

Japanese wisteria displays incredibly long, luxurious and fragrant racemes during the Wisteria Festival in Tokyo.

Pruning has the benefit of stimulating bloom, and it helps a zealous vine behave. A pruning schedule is more important for the vigorous Kentucky wisteria, so if your lifestyle does not allow for that maintenance routine, plant the American version or delegate that twice yearly task to a professional landscape service. If you enjoy grooming your plants and find the regimen of tending to nature therapeutic, training your vine will be rewarding.

The vine you buy will likely have several main stems attached to upright canes. When you plant, select one to three of the best stems and remove the rest. Gently bind them to a strong support (metal or a thick wooden post), and keep the main stems free of side shoots through a yearly pruning regimen, summer and winter.

In August, cut back each shoot from the main stems so that only seven buds remain; in January, reduce those to three buds. Then sit back and wait for the boisterous bloom show to begin. Step lively into spring. Jazz up your great outdoors with a native rendition that strikes a familiar note — and one that “Ain’t Misbehavin’.”

 

Careful pruning of growth back to the main branches encourages bloom on this magnificent wisteria while keeping it under control. The vine swoops gracefully without taking over the roof tiles.

Careful pruning of growth back to the main branches encourages bloom on this magnificent wisteria while keeping it under control. The vine swoops gracefully without taking over the roof tiles.

Tidy and mannerly American wisteria grows on a picket fence in Colonial Williamsburg, requiring little to no pruning.

Tidy and mannerly American wisteria grows on a picket fence in Colonial Williamsburg, requiring little to no pruning.