Wisteria is one of the top-class flowers among climbing plants. To ensure that the magnificent fairy tale of flowers is repeated every spring, the fast-growing ornamental tree requires courageous pruning twice a year. If pruning is missed in winter and summer, the wisteria will grow uncontrollably, lose a lot of its willingness to bloom and can even damage buildings. These instructions explain in detail when and how to professionally prune a wisteria on its trellis.
cutting guide
Instructions for the maintenance cut in two steps
The cut for the maintenance cut always follows identical premises. This applies regardless of whether a wisteria is used to green a facade, pergola, wall trellis or fence. This central cutting measure takes place in two stages.
the first stage pursues the goal of thoroughly thinning out and trimming the entire shrub so that light and air reach all regions of the shrub. In addition, work is being done to ensure that the wisteria invests all its energy in planting the buds for the next flowering period in autumn. the second stage focused on the short shoots.
Since a wisteria bears its flowers on the old short wood, cut here a second time a few months later to promote the willingness to bloom for the coming spring. All relevant aspects around the two phases of the main cut are explained in detail below.
First cut
First cut in late summer
The scissors rest on a well-established wisteria as long as the magnificent shrub is in bloom. Around 6 to 8 weeks after the end of the flowering period, the time window opens to cut the wisteria between the end of July and the beginning of August.
Here's how to get it right:
- wear long-sleeved clothing and gloves to protect against the toxic alkaloids
- Prune faded and young shoots rigorously above the 4th eye
- radically cut proliferating, over-aged branches down to the trunk
- completely remove all old, poisonous fruit stalks
At the end of this pruning measure, you have removed all branches that are too dense and thinned out the shoots and leaves underneath. Please note that without access to light, leaves do not produce energy that is essential for lush flowering. Also cut off any shoots that sprout from the rootstock. Grafted Wisteria are fast-growing water shoots that strive to overgrow the noble part of the wild rootstock.
second cut
Second cut in late winter
As soon as the buds swell in late winter or early spring, the second stage of maintenance pruning is on the agenda. When exactly you make this pruning is determined by the weather. It should be a frost-free, overcast, dry day between late February and mid-March.
Now the focus is on the short shoots, because here it is decided in which dimensions the wisteria floods the spring garden with its flower clusters.
This simple cut is rewarded with a lush abundance of flowers:
- Prune the shoots shortened in late summer again, leaving only 2 or 3 buds
- Buds are located at the base of a spur and are noticeably thicker than a leaf node
From year to year, thickened ends develop on the short shoots, which bloom particularly vigorously. Nevertheless, sooner or later the willingness to flower decreases on older short shoots because they age. Then the time has come for a generational change. The old short shoots must gradually give way to the trunk in order to make room for young branches, which you prune twice a year according to the pruning explained.
education cut
Training cut on pergola
Training cut on pergola and rose arch
With a young wisteria, you can conjure up breathtaking flower images in the garden along a shapely trellis. Creative hobby gardeners like to use a pergola or a rose arch. The upbringing only has a chance of success if the majestic climbing shrub is still developing. Furthermore, the climbing aid should be made of solid material to support the ever-expanding weight of a wisteria.
The upbringing proceeds as desired by tying the two main trunks to the climbing aid in a spiral. By shortening the respective annual shoots of the main stems to a length of one meter in late summer, you cause a sap accumulation, which significantly promotes the formation of flowers. Guide the young shoots sprouting from the main shoots along the pergola and cut them every year in late summer and winter in the stages explained here.
Education cut on wall trellis
Properly mounted on a stable wall trellis, you can create a picturesque backdrop with a wisteria. Although horizontal cultivation produces the most flowering wisteria, the climbing plant also meets expectations in the vertical direction with professional pruning.
That is how it goes:
- select the strongest shoot for the stem and prune to a height of 70 to 90 cm
- remove all side branches on trunk
- connect the shortened leader to the climbing aid
- in summer leave only 2 side shoots and tie them to the trellis at a 45-degree angle
- cut these two side branches in July/August to a length of 10 to 15 cm
- in the second winter, cut off the leader at a distance of 80 cm above the top branch
- in the following summer direct the next pair of side shoots diagonally upwards
- at the same time shorten the branches of these side shoots to a length of 15 cm
- Cut off all superfluous, disturbing branches on the trunk
Please follow these pruning rules until a sufficient number of pairs of side branches has developed on the wisteria to lushly green the trellis. Once the first flowering period has unfolded after 3 to 4 years (for a grafted wisteria) or after 7 to 10 years (for a seedling-propagated Wisteria), the training pruning leads to the maintenance pruning.
standard
Upbringing to the high trunk
Wisteria is one of the few climbing plants that can support a crown themselves as they grow. In order to raise the opulent flowering shrub to a standard, the pruning measures on a young plant are primarily aimed at a strong trunk. Until the leading shoot has developed into a supporting trunk, it is supported with 3 posts. These should already correspond to the height of the adult standard tree. Thanks to the impressive vigour, pruning the shoots to form a crown is uncomplicated.
Follow these steps correctly:
- shorten the leading shoot by a third on a grafted wisteria from the tree nursery in the spring
- Drive 3 stable posts into the ground around the leading drive
- fasten the future trunk to the posts with wide binding material
- Except for 3 or 4 main branches, remove all side shoots from the trunk
- fix these main branches with wire in the desired crown shape until they support the side branches
- cut all new branches in half in late summer
- connect the lead drive parallel to the growth
Experience has shown that the leading shoot has reached the ideal height for a standard in the second year. At the end of February/beginning of March, the shoots pruned in late summer are shortened to 2 buds. As a result, consistently remove all side shoots on the trunk that are not involved in shaping the crown.
Please ensure that the supporting wire does not grow into the bark of the main branches. Until they can carry their load, leave either none or just a few side shoots. Crown formation is usually complete in the third year. From this point on, subject the crown branches to the annual maintenance cut, regularly remove superfluous stem shoots and cut off water shoots on the rootstock.