The wisteria plant is a climbing vine that produces flowers and, when uninhibited, can stretch to cover up to 30 feet of space, either horizontally or upward on a trellis, wall or support. The blooms of the wisteria are often the most delightful part of the plant, and the frequency and rate of blooming is important to growers.
Time to Bloom
Unlike many flowers that often bloom within the same season you plant them, wisteria needs time to stretch out and establish itself before it sprouts its trademark blooms. When planted from seed directly into a garden or container, the plant experiences a long stretch to maturity. The vine will not produce blooms for 10 to 15 years after planting. If you plant a wisteria from a cutting or from a graft off a healthy plant, you will likely see blooms before that time, but it may still take three to seven years to bloom.
Frequency of Blooms
Wisteria flowers bloom once per year. The blooms appear in mid- to late spring, in May or June in most places. The plant can take up to two months for all of its blooms to show through in their entirety. Through a process called deadheading, you can achieve a second bloom in late summer or early fall, generally in September. Observe the wisteria vine and prune away flower heads as soon as they wilt or droop. This may lead to a second blooming later in the season. This is not always the case, however, and depends on growing conditions as well.
Description of Blooms
When it blooms, the wisteria produces vibrant flowers in multiple colors, including purple or lavender, mauve, blue, white and pink. The flowers sprout in small bundles that extend up to 18 inches across the vine, before a space that leads to another group of flowers. Wisteria also produces fruits that look like flattened pea pods.
The wisteria vine needs full sunlight, which means that you must allow at least six hours of direct sunlight exposure to the vine each day to ensure full, vibrant blooming. When you fertilize the plant, use a low-nitrogen or balanced fertilizer. High nitrogen levels in the soil encourage the vine to grow, but not the flowers. Regular pruning in early summer keeps the vine in check and encourages new growth to produce blooms the following season.