The vigor of the plant makes it adaptable to many forms. Wisteria may be shaped into a shrub or standard, trained against a building or lattice, or grown on a pergola or arbor. Wisteria floribunda is a desirable selection to grow on pergolas and arbors because its long flowers hang dramatically through the top. Only one plant is usually needed to cover an entire structure since it is, like other species of wisteria, such a vigorous grower. Planting two vines at opposite ends, however, gives a structure visual balance and affords a gardener the opportunity to feature two different cultivars on the same structure.
Start with a sturdy structure
Training wisteria to grow on a pergola or arbor is a practice that requires careful planning. In order to successfully use these structures, they must be made of a stout, weather-resistant material like cedar and set securely in the ground with concrete footings. Wisteria is infamous for pulling down its supports, so don’t be afraid to overbuild a pergola or arbor. I recommend that the posts be made of 4×4 lumber and the crosspieces of 2×4 lumber at least.
Train vines to climb
To begin training a new plant onto a pergola or arbor, allow two or three young shoots to twine loosely around each other and the post as they grow. This will help to provide added interest to the plant’s structure, since the woody stems become contorted and picturesque with maturity. The young shoots need to be secured to the post as they climb. To do this, attach a 14-gauge galvanized (or similar) wire using eye hooks, spaced about 18 inches apart, along two opposite sides of the post (or on all four sides for extra support). As the shoots grow, tie them as needed to the wire using gardening twine. Allow some slack as they grow to create a more attractive habit and to prevent the plant from putting heavy tension on the structure as the plant matures.
Once the shoots have reached the top of the arbor, head them back (prune off the tips) to encourage side shoots, which will spread across the top of the supports and produce flowers. As the plant grows and becomes more stable across the top of the structure, the training ties on the post will become unnecessary. It’s a good idea to remove them to prevent the plant from being girdled as it grows.