Thanks to its long flower clusters, the wisteria is a real feast for the eyes. It causes all the more grief for the hobby gardener if he doesn't want to bloom or doesn't want to bloom anymore. This article explains why this can be and how best to counteract it with eleven practical tips.
Wisteria
Wisteria is a lush climbing plant. Their grape-like flowers fill the garden with life and amaze the viewer. However, one hears and reads again and again that one's own wisteria simply does not want to bloom. The possible causes are manifold. This guide explains the main reasons. In addition, the practical tips help to solve the respective problem.
location
Choose the right location
If the location is not right, it is quite possible that the wisteria does not like to bloom. It needs a warm and sunny place to develop optimally. It also thrives in semi-shade, but with a significantly smaller number of flowers. It is essential to avoid full shade.
Tip: Ideally, this plant is planted on a south wall.
It is also important not to place the climbing plant too close to a rain gutter. There she could climb up and cause considerable damage.
Tip: Even if the proximity to a gutter is taboo - the Wisteria definitely needs a climbing aid, as it grows very quickly. It is best to rely on stable rod-like supports. Wire ropes are also very suitable. The only thing that should be avoided is wooden scaffolding, because the blue rain will destroy it.
From all of the above, it also follows that this plant requires a lot of space in the garden. This has to be taken into account when planting.
floor
Pay attention to lime-poor soil
A very calcareous soil can lead to the wisteria refusing to show its intense blooms. If there is too much lime, its leaves turn yellow and often fall off.
This is how you can test the lime content yourself, you need:
- 8 to 10 percent hydrochloric acid (chemical: HCl)
- Watch glass or porcelain bowl
- suction pipette
- teaspoon
- soil sample
How to proceed:
- put a teaspoon of a dry soil sample on the watch glass or porcelain dish
Notice: Take the soil sample directly at the location of the blue rain.
- Fill pipette with hydrochloric acid
- put a drop of hydrochloric acid on the edge of the sample
- monitor the level of foaming
Key:
- a) no visible and audible roaring - no limescale
- b) hissing only audible close to the ear - calcium content < 1%
- c) weak, short effervescence - lime content 1 to 2%
- d) clear, short effervescence - cold portion 2 to 4%
- e) strong, long-lasting effervescence - lime content > 5%
Is the result attached? a) until c), so far everything is fine. Otherwise, from now on you should only water with rainwater to reduce the lime content.
underground
Ensure the ideal substrate
In addition to being low or free of lime, the soil must also have a few other properties in order to function as the perfect substrate for the wisteria. It should be like this.
- rich in humus
- acidic to neutral
- moist but permeable
Even if just one of these points is wrong, it can happen that the plant does not flower as desired.
young plant
Stay patient or change your mind
Perhaps the lack of flowering is simply due to the fact that the wisteria is too young for it. Depending on the variety, the plant flowers for the first time after two to three years or much later. Some species even make the hobby gardener wait a full ten years before they develop flowers.
Tip: Grafted specimens flower much earlier than ungrafted plants. The latter are often only ready for the first time after many years.
Be careful, wisteria propagated from seeds rarely flowers. Therefore, one should rely on cuttings propagation, ideally in combination with grafting. The best thing to do is find out how things are with your own wisteria with regard to the points described. And until it blooms, the rich foliage, which appears light green in spring and more yellow in autumn, will also inspire enthusiasm.
To cut
Prune the plant properly for the first two years
The right cut plays an important role right from the start. If you make a mistake here, it is quite possible that flowering will not occur. Wisteria not only grows abundantly, but also very quickly. That's why you have to lend a hand in the first two years.
- shorten the lower side shoots except for two eyes
- Remove all shoots close to the ground and wild shoots
Cut wisteria properly from the third year
It continues with the right cutting. From the third year there are a few more things to consider.
- Cut back the new shoots by half in late summer (end of August).
Important: The side shoots must not be longer than the main frame.
- the wisteria continues to grow until frost, so in spring you will usually find new growths on the shoots cut in summer - cut them back down to three to five eyes at the end of February/beginning of March
- Completely remove shoots that produce little or no green
- when cutting back, check the attachment of the climbing aid and adjust if necessary
If you stick to all the points, you can usually look forward to a rich flowering in the same year. Conversely, mistakes made when cutting can reduce the willingness to flower.
Tip: If the climbing shoots are allowed to continue growing unhindered, the wisteria will lapse into vegetative growth behavior, which will have a negative effect on the flowering.
Incidentally, you can use the clippings to increase the wisteria. But more on that in another guide.
pour
Supply blue rain with plenty of water
The Wisteria is very demanding when it comes to the water supply. In summer you should give the tree plenty of water - preferably by putting the lower part of the pot in the wet. But, don't keep the wisteria soaking wet all year round.
If you don't sufficiently quench the plant's thirst, don't be surprised if it doesn't bloom or hardly blooms in the new year. By the way, despite the summer “bath”, the roots do not rot.
repot
Don't repot the plant too often
Some hobby gardeners tend to repot their wisteria relatively often. However, this can significantly limit the willingness to bloom.
Tip: You should not repot the wisteria more often than every five years.
Note: The type of water supply and repotting described above go hand in hand. Due to the rare repotting, the root ball gradually compacts. This is just as necessary for a good flower set and therefore desirable. However, compaction makes it difficult to water sufficiently from above. Especially in summer, the wisteria needs a lot of water - that's why the water bowl is recommended.
Fertilize
Fertilize properly for a good nutrient base
Fertilizing is a critical point for almost every plant, including wisteria. Even the slightest mistake can inhibit flowering. Therefore, you should pay close attention to when and how much you fertilize.
Tip: Fertilize heavily after flowering, until about July. Then give less.
In this way it is ensured that the wisteria sets the flower buds for the next year and that the growth of foliage over the summer time is limited.
Do not remove nodule bacteria
Wisteria belongs to the butterfly family. So-called nodule bacteria (rhizobia) can be found on the roots of this group of plants. Inexperienced/ignorant hobby gardeners often mistake the nodules for root canker and cut them off when repotting. However, this is wrong and should be avoided at all costs if you want to guarantee a beautiful flower!
The bacteria have an important task: They absorb elementary nitrogen in a symbiosis with the wisteria and make it available to the plant (to put it simply).
Revive
Encourage old wisteria to bloom
If an old wisteria is no longer blooming, you can try to (re)animate it again with a courageous pruning. In the coming years, the new shoots should be better protected. Flowering may then occur after two to three years.
Important: Of course, this only works if the plant has no other problems - i.e. other reasons for the lack of flowering can be ruled out.