Wisterias won't bloom?

7-year wait for Wisteria to flower

By: Sandy Feather ©2009
Penn State Extension

Q. I have a seven-year-old wisteria that has never flowered. Is there anything I can do to encourage it to bloom?

A. Failure to flower is the most common problem gardeners have with wisteria. Wisteria naturally has a long juvenile period, especially if your plant was grown from seed. It is not unusual for seed-grown plants to take 10-15 years to flower, sometimes even longer.  Grafted plants or those grown from cuttings typically bloom faster.

Wisteria in mid-May

Reasons your wisteria may fail to bloom:

  • Not enough sun - Wisterian requires full sun to bloom well.
  • Excessive nitrogen fertilization that stimulates vegetative growth at the expense of flowering.
  • Heavy winter or spring pruning that also stimulates vegetative growth at the expense of flowering.
  • Improper pruning that removes flower buds (Wisteria sets its flower buds the season before)
  • Unusually severe winter weather that kills flower buds.


White Wisteria
White Wisteria

FERTILIZATION: If changing cultural practices still does not result in a flowering vine, apply three to five pounds of superphosphate (0-20-0) in early spring. A heavy phosphorous application has been known to stimulate flower bud formation.

ROOT PRUNING: Another strategy to encourage flowering is to root prune wisteria in September. Simply push your spade into the soil the full length of the blade all the way around the base of the plant, three to four feet away from the trunk. You arenít digging it up, just threatening it.

TRIMMING WISTERIA: You should also prune extremely long and vigorously growing stems in late spring. This helps keep the vine in check and promote flowering on established plants.


Photos of Perennials (A thru M)

Photos of Perennials (N thru Z)

Grapes shriveling up


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