Non flowering wisteria, what does it need?

Hello Nbm, I recommend dissolving 2 tablespoons of Epson Salt in a gallon of water. Pour this solution onto the base of your wisteria's down where the plant meets the soil. Then water them real good. That will help the roots receive the Epson Salt. This process will put enzymes back in your soil. You should see improvement soon. Best of luck.

I think perhaps the plant is finishing up becoming well rooted and being acclimated to the climate. I would feed w Miracle Grow as without soil analysis, you do not know a single additive that will do the trick. MG contains all the basic additives for flowers.

From my favorite gardening website: https://www.gardeningknowhow.com/ornamental/vines/wisteria/wisteria-blooming-problems.htm

How To Get Wisteria To Bloom – Fix Wisteria Blooming Problems

By Heather Rhoades

Wisteria is a vine that is well known for its vigorous growth and are just as notorious for being reluctant to bloom. When a wisteria won’t bloom, many gardeners get frustrated and ask, “Why is my wisteria not blooming and what is the secret on how to get wisteria to bloom?” There is no secret to fixing wisteria blooming problems. A little knowledge can help you quickly fix the problem. Let’s take a look at what you need to do to understand how to get a wisteria to flower.

Reasons Why a Wisteria Won’t Bloom

The most likely reason your wisteria won’t bloom is due to too much nitrogen. When a wisteria plant has too much nitrogen, it will have plenty of foliage growth, but very little and maybe no blooms.

Another reason for wisteria blooming problems is the environment they are growing in. Wisteria vines that lack full sun or proper drainage may be stressed, and while they will grow leaves, they will not bloom.

Improper fertilization may also be the answer to the question of why is my wisteria not blooming. Fertilizing in the spring can encourage leaf growth and discourage blooms.

Lack of maturity may also be the culprit. Most wisteria bought in plant nurseries are the proper age to start blooming; but if your wisteria was grown from seed, or given to you by a friend, it simply may not be old enough to flower yet. Wisteria must be seven to 15 years old before they are old enough to bloom!

The last, and least likely, reason a wisteria won’t bloom is over pruning. Over pruning will remove the flower buds. It is extremely difficult to over prune a wisteria, though.

How to Get Wisteria to Bloom

Since too much nitrogen is the most common cause of wisteria blooming problems, the easiest thing to do is to make sure this is not a problem. There are two ways to correct this cause of a wisteria not blooming. The first is too add phosphorus to the soil. This is done by applying a phosphate fertilizer. Phosphorus encourages wisteria blossoms and helps to balance out the nitrogen.

The other way to reduce the amount of nitrogen a wisteria plant is getting is to root prune the plant. This is done by taking a shovel and driving it into the ground in a circle around the wisteria. Make sure that you do root pruning at least 3 feet from the trunk, as root pruning too close to the plant can kill it. Using root pruning as a way how to get a wisteria to flower reduces the amount of roots and, by default, the amount of nitrogen those roots take up.

If these methods do not work to correct your wisteria blooming problems, you can check to see if one of the other reasons may be the problem. Is the plant getting enough sun? Is there proper drainage? Are you fertilizing at the right time, which is in the fall? Are you pruning properly? And is your wisteria old enough to bloom.

Wondering why is my wisteria not blooming is frustrating when you don’t know the answer. But now that you know how to get wisteria to bloom, you can start to enjoy the lovely flowers a wisteria produces.

I sprinkle blood meal around my wisteria in January after I prune it. It wasn't blooming until I started using blood meal.

Epsom salt will really help with the proper drainage :)

http://homeguides.sfgate.com/long-before-wisteria-plant-blooms-first-time-69737.html