When Does Wisteria Bloom?

Flowers and Bloom Time

• Wisterias flowers are pealike in form and grow in pendulous clusters, blooming in late spring. Flower colors include pink, lilac blue, bluish-purple, or white. The two most-used varieties of wisteria include Chinese wisteria, Wisteria chinensis, and Japanese wisteria, Wisteria floribunda. Both varieties have violet blue, fragrant flowers. The 8- to 20-inch-long clusters of flowers are followed by green, flat pods, typical of plants from the pea family.

Size

• The vigorously growing vine has a growth pace of nearly 10 feet per year and requires a strong trellis or structural support to climb. Wisterias have a mature height of 25 feet or more under optimal growth conditions. The twining stems help the plant to climb. Established plants develop woody trunks with a diameter of several inches. Plants propagated with cuttings flower earlier than those grown with seed.

Growth Requirements

• Plant wisteria in an area that receives at least six hours of direct sun every day. Though the plant adapts to most soil types, growth is best in a moist, fertile, deep soil with a preferred pH of 6.0 to 7.0. Amend planting site with organic material such as well-rotted manure, peat moss or compost prior to planting. Avoid planting in sites where the stems can grow into and clog gutters of buildings. Wisteria is hardy in U.S. Department of Agriculture plant zones 5 to 9.

Care Suggestions

• Obtain healthy plants that have been propagated with cuttings. Avoid the use of seedling vines as the genetic variability of wisteria makes their blooming habit unpredictable. Perform all pruning of the plant during full sun, recommends the Purdue Cooperative Extension. Since the vines produce flowers on the previous year wood, do not prune plants before summer. Avoid excessive use of nitrogen and planting in shade as this affects the flowering. Plants that are deficient in phosphorus also produce fewer flowers.