VERSATILE WISTERIA VINES
Wisteria is a colorful, versatile, fast growing, easy to care for vine. The hanging clusters of flowers provide quite a show in the late spring.
It can be grown as a vine, a tree or a shrub. It is an ideal vine to use against a wall, fence, trellis or arbor. With a little special training it can be coaxed into a tree. With pruning it can be maintained as a shrub.
The two most common species are W. floribunda , (the Japanese one) and W. sinensis, (the Chinese one). Here' the difference between the two:
Wisteria floribunda (Japanese wisteria) - has large 12 to 18-inch clusters of flowers. It usually flowers as the leaves are developing. The fragrant flower clusters come in violet-blue, white, pink and several in between shades. It flowers in May and June.
Wisteria sinensis (Chinese wisteria) - it flowers before the vine begins to leaf-out. Flowers are a bit smaller, ranging from 9 to 12 inches in length. Most have a mild sweet fragance. The white and violet-blue varieties are the most popular. This type tends to bloom at an earlier age and most open at the same time creating quite a flowering display in May.
There are other species, but these two seem to be the most popular and readily available in the west. However, the others do grow here and you will occasionally find them in specialty gardens.
LOCATION AND PLANTING
Most nurseries and garden centers have their finest selection of vines in late winter and throughout the spring. Contain grown vines are also often available at other times throughout the year.
Wisteria loves a bright sunny spot in the garden. However, we have three vines in our garden and one is in full sun, the other two in part sun and shade. All three do equally well.
Wisteria is difficult to move once established, so it is important to plant where it can remain undisturbed. I should rephrase this comment, because we moved an old one, and it transplanted fine, but it took the plant almost five years to fully recoup.
Wisteria is one plant that seems to thrive on a certain amount of neglect. However, planting time is the only time you can get nutrients and soil conditioners directly to the root zone. So mix generous amounts of compost, peat moss or processed manure with your existing soil. Provide good drainage and just a little bit of transplanting fertilizer. Be certain to provide staking support immediately. Otherwise, the weight of the vines could cause them to break from the main stem as the plant grows.
To train a young vine into a tree, simply prune back all vines, except the strongest, sturdiest one. Stake it and train it upright, supporting it so it will grow as a tree trunk. Then when it reaches the desired height simply prune out the tip growth. From this point it should branch out and form a tree. Use a husky pipe or 4 X4" post to secure the trunk and keep it from wind whipping or breaking. As you are training the trunk upright, you may find a few shoots trying to form on the trunk, keep them pinched off, or they will form side shoots and the tree effect will be lost.
Severe pruning, if needed, is done during the winter dormant season months of November, December, January and February. Some July pruning can be done, to help control the rampant growth of the vines. Otherwise, you end up with a tangled mess of intertwined vines. The dormant season pruning is the severe pruning, when one should cut the leader vines back to the desired height. Then prune the side shoots (those growing from the main leaders) back to the second or third dormant bud. This is where good judgment must be used, because the flower buds form the previous summer, and if you prune too severely, of course you will be cutting off all the potential new flower buds. I think the most important consideration is proper pruning at the correct time. If allowed to grow unattended the vines may reach 50 feet or more.
FERTILIZING AND WATERING
I put these two factors together, because if you over-water or over-fertilize wisteria vines, your chance of getting them to flower is greatly reduced. As mentioned earlier, wisteria thrives on a certain amount of neglect. The prettiest wisteria and grapevines I have ever seen were around an abandon house, where they existed on what 'Mother Nature' provided in moisture, sun and nutrients.
However, if the vines are off-color or obviously in need of feeding, feed them with a 'Rose type' plant food. The best times to feed them is in late winter or mid-spring.
Water sparingly throughout the summer. If there's a prolonged warm (or hot) spell, they obviously will need watering attention. If a few leaves show signs of wilting, then be certain they get the moisture they need. The roots are quite robust and over a period of time may find their own source of moisture.
VINES THAT DON'T FLOWER
If you have an old plant that has not been flowering as well as it should, root pruning in the fall will slow growth and often aid in the development of additional flowers in future years.
PROPAGATION OF WISTERIA
The vines you purchase have usually been grafted, layered or taken from cuttings. So if you want to start additional vines from your own plant, layering the lower side shoots is the best procedure to follow. Do this in the spring. Actually lower growing vines will often come into contact with the soil and root on their own. Simply cut those rooted vines away from the mother plant and you have a new vine. Best time to do this is in springtime.
A 12 to 18 inch tip of the vine can also often be started in water alone. If you add a little rooting hormone to the water, it may help speed up the rooting process. Smaller cuttings 6 to 9 inches long can also be started in soil. Whether you do it in soil or water, the best time is to take these cuttings in the late winter, just before the new growth starts.
New vines can also be started from seed, but seedlings are slow to flower. It may take 8 to 10 years for the first blooms to appear.
INSECT AND DISEASES
Wisteria is a pretty trouble free vine and is seldom bothered by insects and only occasionally by problems like mildew. Should problems occur, consult your local Certified Nursery-person for specific recommendations.