General Care

• Provide optimal, consistent care to your wisteria tree as a means of promoting the healthiest plants possible. Healthier plants have a greater capacity for overcoming any problems that come their way. Grow wisteria in locations that offer a minimum of six hours of full, direct sunlight on a daily basis. Sufficient sunlight is particularly important in successful flowering. Cultivate wisteria plants in moist, well-drained soil with a pH of 6 to 7. Irrigate to keep soil moist during drought conditions or once foliage wilts as wisteria cannot tolerate dry sites.
  
  

Normal Flowering

• Wisteria trees do not always have flowers, nor do they bloom regularly once they begin flowering. Before becoming concerned, determine the age of your wisteria tree. Particularly when wisteria is grown from a seed, it remains in an immature flowerless stage for anywhere from seven to 15 years. If you feel that your tree should be flowering or are unsure about the age of your plant, contact your local county extension agent for assistance. Simply maintain appropriate care for successful growth and healthy bloom once your wisteria becomes established.
  
  

Bloom Problems

• If your wisteria tree is established, consider some of the potential problems that may be causing bloom failure. Avoid overfertilization of wisterias, especially nitrogen fertilizers. Nitrogen promotes the growth of foliage and decreases the potential for the development of flowers. Improper pruning also reduces flowering. In addition, pruning during the wrong seasons and removing flower buds kills the new flower growth before it has a chance to bloom.
  
  

Solutions

• The problems affecting the flowering of your wisteria are easily rectified with some maintenance changes. For fertilization, apply a phosphate fertilizer that does not contain nitrogen. Phosphorous encourages bloom whereas nitrogen decreases the likelihood of flowering, according to the New Mexico State University. Use a "superphosphate," 0-20-0, during the end of spring or beginning of summer, recommends the University of Illinois.
  
  For correct pruning, first prune heavily during the summer and prune lightly during the winter. Also consider a method called "root pruning" that slows the growth of roots to allow for flowering. With a shovel or spade, dig into the soil approximately 3 feet from the wisteria's trunk. Cut around the entire plant to a depth of up to 24 inches.