Q: Is there such a thing as a non-blooming wisteria? I live on Long Island, NY. The vine was grown from seed, and has never bloomed in 20 years. I have tried pruning at different times of the year.
Barb M.
A: Wisteria grown from seed are know to have an extremely long juvenile period when they do not bloom. This can last from 10 to 15 years or longer. Some species of wisteria take longer to reach maturity than others and because your vine was grown from seed, it could have a long juvenile stage in it's genetics. Since your wisteria is now at 20 years, it may just be one of those "slow bloomers" and will bloom when it is ready; but there may be other factors at work as well.
Wisteria needs at least six hours of sunlight each day to bloom. Have your soil tested to ensure the pH is within the 6.0 - 7.0 range for best blooming. Apply an organic mulch to maintain moisture in the soil. Wisteria blooms on "old wood", which is the previous year's growth; avoid pruning in winter or spring which trims off the "old wood" and encourages vegetative growth over flower production. Avoid high nitrogen fertilizer which also encourages vegetative growth over flower production. If your soil test indicates a low level of phosphorus, apply an application of superphosphate (0-20-0) in spring at a rate of 3-5 lbs per 100 square feet.
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