Gardening : If Wisteria Vine Too Big, Try Making It a Tree

When is a vine not a vine? When it’s a tree.

If you pine for the vine called Wisteria, but don’t have the space to accommodate its spreading stems and cascading blossoms, branch out in another direction: Plant a tree wisteria, which is actually the vine trained to tree shape.

There are three ways to get growing:

Buy the trained plant. These will already be about three years old and about five feet tall, with a good root system and a healthy head of foliage. It will come from the nursery tied with garden tape at several points to a tall stake.

The trunk must be kept free of shoots and suckers. To shape the top, tie garden tape to the ends of four or five branches and draw them downward toward the trunk--not all the way to it, just enough to form an arc. Do the same thing with some of the top branches that are growing upward, so that an umbrella or “weeping” shape is gradually formed. Remove any crossing branches at the top.

Train your own. Buy the small wisteria shrub (about 18 to 24 inches high). It will have three or four branches. Select the strongest, straightest one to serve as the trunk. Clip off the others. With garden tape, fasten the trunk loosely at several points to a stake five or six feet tall. Trim off any side growth as the tree develops. (This process will take about two years.) When it is five or six feet high, with a good “head,” start the shaping described previously, concerning the trained plant.

Bare root: This will already be in tree shape, with a single trunk. Fasten it to a stake and follow the foregoing procedures. The bare-root tree will usually bloom the first year.

It’s important to know that you can choose between two wisteria types at the nursery: the seedling, which takes up to three years to bloom, and the grafted plant, which should bloom the first year it’s planted. (There’s a considerable difference in price.)

If the soil in your garden is well-drained, Frank Burkard, of Burkard Nursery in Pasadena, recommends a planting mixture of 50% garden soil and 50% azalea mix, with a little leafmold added, if possible. If your soil is the heavy type and full of clay, L. E. Cooke Co. growers in Visalia, suggest elevating the plant slightly: Make the hole larger and deeper and toss a couple of spadefuls of sand onto the bottom. (A reminder for the beginning gardener: “Sand,” in this case, means the coarse washed “river” sand you get from the nursery, not beach sand, which is salty.)

As to watering needs, thorough, slow, deep watering is vital, but then allow the soil to dry out before you water again. Wisteria roots tend to rot if kept constantly moist.

If later on you decide to alter or expand your exterior decoration, this hardy, deciduous free-standing tree will gladly grow your way. Form an arbor of a trellis and 4 by 4 supports; let the upper branches grow horizontally and, presto change-o, it’s a vine again.