Some wisteria varieties can wreak havoc in the garden, crowding out treasured climbing roses, clematis and other plants. Planting a vigorous variety against a wall of the house or a porch pillar, could in time do damage to both. All wisterias are vigorous once they're happily situated, but in the right circumstances can behave like garden villains, knocking out everything in their paths.
Chinese Wisteria, W. sinensis
There is one Chinese wisteria, W. sinensis, in a garden in Sierra Madre, that over a century, has managed to engulf an acre of land, growing at a rate of 14" per day. In the 1930s, it also engulfed the house it was growing against. This wisteria has become a tourist attraction as each year in March, thousands of people visit during the Sierra Madre Wisteria Festival to view this horticultural curiosity.
The Chinese wisterias can grow to 100 feet or more, and gardeners do love this vine. It is strongly scented, and very floriferous with long flower racemes up to 12 inches. There are white, dark purple and mauve varieties, and among these are doubles and semi-double flowers.
It is extremely vigorous and it's advisable not to grow it on the walls of the house where it can find its way under the siding and into the eaves and gutters.The Chinese wisterias are better suited to larger properties and on pillars or steel structures away from the house or boundary trees, unless the gardener is committed to a regular pruning routine. And growing this variety is indeed a commitment.
Japanese Wisteria, W. floribunda
Like the Chinese wisteria, the Japanese W. floribunda is also a vigorous vine, with massive trunks. In time, it too, can grow quite big, up to 30 feet tall. The flower racemes are also very fragrant, and similar in length as the Chinese variety.
W. floribunda "Macrobotrys" is a lilac blue to purple Japanese wisteria with beautiful flower racemes up to 36 inches long.
The Asian wisterias need to be controlled. New shoots will have to kept in check and it's an ongoing battle. But for gardeners who love this plant, the effort is worth it for its scent and the richness of the flower racemes in spring.
Less Vigorous American Wisteria W. frutescens
The American wisterias have less vigor and although this vine still needs to be kept in check with pruning, it is more easily maintained. Their scent is not as pungent as the Asian varieties.
W. frutescens will grow to 20 or 30 feet. The flower racemes are shorter than the that of the Asian varieties, approximately 5 to 6 inches in length. Popular varieties include "Amethyst Falls', and 'Nivea'.
Kentucky Wisteria, W. macrostachya is also recommended as a gentler kinder vine. It is hardy to Zone 5 and begins to flower within two to three years. It's also a repeat bloomer.
Training Wisteria
If wisteria is left to grow and wander at will, it will. And it will do so with gusto. Wisteria needs to be kept in check, not just to ensure the plant remains beautiful, but to ensure it doesn't cause damage to or interfere with other parts of your garden, as well as your neighbors.
Check for new shoots low down, and just below soil or mulch level and snap or clip them off. Shape the plant, by clipping off new shoots. Good pruning will ensure there is less fauna and more flora the next growing season.
The Royal Horticultural Society suggests pruning wisteria twice yearly -- once in mid-summer, to keep it from getting out of control and again in mid-winter, but just to the flower buds, offering a healthy start to the spring growing season.
Buying a Wisteria
Buy a wisteria already in flower or at least one of a good size. Wisteria seedlings can take 10 to 20 years to produce flowers, so potted cultivars are the better choice. Small plants can take up to seven years to produce flowers, so this is a vine that can test the gardener's patience.
Asian wisteria is generally hardy to Zone 5. The hardiest are Kentucky wisteria, W. macrostachya with some wisteria cultivars hardy to zone 3.
Lorraine Syratt - Lorraine Syratt is a freelance writer, gardener and part-time antique dealer. Please see her full profile for more information.
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