Wisteria plants are part of the pea family. These plants are vines that are often grown in the form of trees and shrubs. Wisteria trees thrive in full sunlight which is at least 6 hours and more per day. Plant their roots in deep, moderately fertile soil that drains well, but stays moist. They prefer neutral to slightly acidic soil.
Wisterias are vigorous twining vines with large green leaves that are divided up into many smaller leaflets. Large clusters of flowers bloom in the spring with pea-like blossoms. These flowers are white, pink, lilac-blue and purple. Flowering is followed by the production of a long, green flattened seed pods. Older wisteria vines grow a twisted, woody trunk that is several inches in diameter.
Wisteria trees are grown as a single trunk to create a tree-form. Tie the wisteria to an upright metal stake to help begin the training. After the vine is 4 to 5 feet tall cut off the top of the vine. Allow side shoots to develop on the upper part of the vine. Remove the side shoots from the lower part of the stem. Prune the side shoots back to 6 to 12 inches each winter until the tree top is as large as you want.
Newly planted wisterias require 1 inch of water each week either by watering or by rainfall. Fertilize the new vine each year. After 3 to 4 years, do not fertilize your wisteria vine unless foliage growth and color is not good. Water established plants only if the foliage wilts.
Wisteria trees grown from seeds remain in a juvenile stage for 10 to 15 years before they bloom. Wisteria vines propagated by stem cuttings from a flowering parent will begin producing blossoms much sooner.
There are 10 species of wisteria vines, but only two that are commonly grown in the home garden. Chinese wisteria (Wisteria sinensis) grows 25 feet or more in length with flower clusters that are 6 to 12 inches long. These flowers open all at once before the foliage has expanded in early to mid-May. Japanese wisteria (Wisteria floribunda) grows 25 feet and blooms while the leaves are expanding. The flowers open from the base of the cluster progressively down towards the tip. The flower clusters grow 12 to 18 inches long in late May.