Wisterias are one of the most beautiful blooming vines. They twine up and around structures, quickly growing into thick tangled masses of an exotic artwork. Their long and fragrant clumps of purple, pink, or white blooms complement its lacy foliage beautifully in late spring or early summer. The whole effect appears so fanciful that one would expect to see unicorns resting beneath its shade.
That being said, wisteria is not for the lazy gardener. It can easily become a nuisance plant, especially if you are not aware of what this gorgeous, but aggressive plant can do. Here’s a little insight into what to expect from your vine.
Wisteria are sold in tiny gallon containers or plastic bags with one or two little branches smaller than your pinky sticking out the top. More often than not, half of these little vines will die over the winter, simply because at this stage they are weak and some varieties are not as hardy as others. If you get them to survive the first winter, they will become hardier and more drought tolerant as they age. Small plants can take up to five years to produce their first blooms, while 5 gal. grafted plants can bloom within a year. Avoid growing wisteria from seed; it will not be true to the mother plant and they can take up to 15 years to bloom!
There are nine different species of wisteria, but three that are found for sale at local nurseries: Chinese, Japanese and American (or Kentucky, which is a sport of the American.)
Chinese wisteria is not quite as hardy as that of the Japanese, but these vines can grow to 70 feet, and can weigh several hundred pounds if left to grow wild. Their sweet smelling flowers produce clusters of blooms 6 to 8 inches long. These plants are generally used to cover walls, but their strong roots can extend 40 feet underground, and can wreak havoc on foundations, sewer lines, and sidewalks.
The Japanese varieties are better for trellises and pergolas, but can still reach 40 to 50 feet and be just as damaging to structures as the Chinese wisteria, if not pruned every winter to control its growth. These are by far the most amazing blooms, producing heavily fragranced clusters a foot long or longer, before the leaves emerge in late spring. ‘Kuchi Beni’ produces 18 inch long purple flower clusters. Var. floribunda ‘alba’ makes 24 inch long white arching sprays and f.‘rosa’ is even longer with pink 30 inch long sprays.
The American and Kentucky varieties are the hardiest by far (z-3), and less invasive, growing 7 to 12 feet. Their blooms are only slightly fragrant, and the small four inch flower clusters bloom only after all the leaves have emerged, and therefore are hidden by the foliage.
Choose a location that is sunny with at least six to eight hours of sun. Plant in well draining soil and keep moist. As the vine grows it will require less water. Cover your new plant with pine needles to help it survive the first year, but after it reaches ten feet, it should be hardy enough to get through the year on its own.
Heavy pruning should be done every winter. You can remove large branches at this time without killing the vine. Heavy pruning will keep the blooms at nose height instead of 40 feet in the air. They all bloom from new growth, so this is important. Always remove suckers, and reserve the light pruning for after it blooms in late spring. You don’t want to inadvertently cut off any flowers!
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