|I have 4 wisteria plants on different properties that are all a minimum of 6 years old and older. I have trimmed them different ways but they will not flower. They grow at least 20 feet a year and look very healthy. What can I do to get them to flower??
| Wisteria is one of the most spectacular vines you can grow - it is also one of the more challenging. Perhaps I should modify that...the vine is easy to grow, the challenge is getting it to flower. I think the youngest wisteria I have heard of producing flowers is 3 years old - and it wasn't a very impressive show. I have a family member who has a 10 year old wisteria with no blooms (we have tried just about everything!) There are many reasons that wisteria fail to bloom. If your nursery sold you a seedling wisteria, it may take 20 years to bloom! Good nursery stock is grown from rooted cuttings. Check with your supplier for this information. Also, wisteria tolerate very little shade if they are to bloom. Excessive vegetative growth suppresses bloom, too. This excessive vegetative growth can be intensified by too much nitrogen during fertilization. When fertilizing your wisteria, I would stick to a superphosphate.
They require specific pruning as well to balance vine and bloom stimulation. If you need more information on pruning, please feel free to submit another question via the database. Sometimes root pruning around the drip line of the vine will stimulate the flowers to form for next year. Just dig down one foot deep all around the drip line breaking any roots you meet. Give these these methods a try!