Pruning Wisteria Plants
Everything you need to know about pruning Wisteria sinensis trees and vines. When to prune a Wisteria vine to encourage heavy bloom. How to keep a standard shapely. Training Wisteria to grow as a free-standing shrub.
Pruning Wisteria is not difficult, but you've got to understand how the plant grows and blooms in order to get it to do as you please.
Chinese Wisteria is an exceptionally vigorous deciduous vine. Unpruned, it will quickly grow into a tangled mass of shoots and dried seed pods. Improper pruning may remove the flowering spurs on which the blooms form. This is the most common reason for failure to flower in older vines.
Proper trimming will keep your vine or tree neat and beautifully productive.
When Should You Prune Wisteria?
In late winter while it is naked. Some gardening reference books will warn you not to do this for fear that you will unwittingly remove the flower buds, but only pruning the vine in summer creates two problems:
- The flower clusters will form on a vine filled with last season's seed pods which will detract from the beauty of the spring display.
- There will be twice as much cutting to do in August while the leaves are still on the shoots. You may find it difficult to see where to make your cuts.
Pruning Wisteria Spurs
Wisteria's flower buds form on short spurs (much like apple blossoms) which grow on the lateral branches.
To cause the vine to produce larger flower clusters which hang freely, shorten the spurs to 6 buds.
Do not remove the entire spur or the plant will not bloom.
If you do not shorten the spurs, the plant will produce more bloom clusters, but they will be smaller and more crowded.
For best results, trim the plants twice per season.
In August: Head back new stems (except those you wish to use to extend the height or length of the vine) to the second bud, and remove long leafless shoots (streamers) before they begin to twine and become tangled .
In Late Winter: Thin out any broken, crossing, or contrary growth. By contrary, I mean any shoots growing in the wrong direction. Remove seed pods and old flower stems.
Head back the remaining side shoots to 12 inches. Cut the flower spur-bearing laterals growing from these side shoots back to 3 buds.
Training a Wisteria Vine
In Time, the Main Stems Will Become Thick and Heavy
The more stems you keep, the more the mature vine will weigh.
Consider the strength of your support when deciding how to train the vine.
- Plant the vine about a foot from its support. Select the main stems you are going to keep and remove all others at the base.
Depending on the size of the support and the amount of growing space you have, you can select one or many main stems. Choose vigorous, upright shoots as these will become the vine's permanent branches.
- If your plant only has one stem and you want it to develop others, cut it back a few inches. This will encourage more shoots to grow.
- Tie the main stems to the support. Let them grow until they reach the desired height. That winter, tip prune them to induce side branching the following spring.
- Follow the pruning instructions above beginning in August.
Training a Wisteria Tree
You can buy a plant that has already been trained to standard, or you can prune any young Wisteria plant into a tree. Here's how:
- Select the strongest, most upward-growing stem to be the trunk. Cut all other stems off at the level of the soil.
- Place a stake beside the trunk, and tie the trunk to the stake as it grows to keep it straight.
- Once the trunk reaches the desired height, pinch out the growing tip to make it branch. Tip prune the new branches after several inches of growth to cause them to branch, as well. Keep doing this until the crown of the tree is as bushy as you want it to be.
- Monitor the trunk for unwanted growth. Rub off any shoots emerging from the trunk as soon as you notice them.
- Each winter, head lateral shoots growing from the crown's main branches back to keep the crown neat.
Growing Wisteria as a Bush
When pruning Wisteria as a free-standing specimen shrub, select several evenly spaced, strong stems to create the basic framework of the bush. Let these grow. Cut back all other stems to 2 leaves or buds.
Keep doing this until the plant grows into a large, self-supporting shrub.
In subsequent years, trim back overly vigorous shoots to maintain the bushy form.
Some of My Other Pruning Guides:
Fast Growing and Fragrant Perennial Flowering Vines
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