The wisteriaWisteria sinensis - Fabaceae
Among the rustic climbers are those with more abundant, fragrant and decorative flowering; at the beginning of spring the wisterias give us large clusters of lilac flowers, very fragrant, which bloom in succession, giving rise to a very prolonged flowering, which lasts for several weeks. Much appreciated for centuries in Europe, in fact they come mainly from China and Japan, although lately species of North American origin are also cultivated in the garden. The most cultivated species is certainly the Wisteria sinensis, of Chinese origin; in the nursery there are also species with particular blooms, hybrids with pink flowers and with variegated leaves.
Very beautiful and elegant, the wisteria is also a plant of easy cultivation, as long as it has a large space where it can be developed. In fact they are very vigorous and long-lived climbers, which can develop their thin branches for a few meters in a single vegetative season.
Even if the wisteria tend to settle for any soil and little sun, young plants should be planted preferably in a very sunny place, with soft and rich soil, burying even mature organic fertilizer in the hole; over the years, the wisteria will greatly widen its root system, giving us the possibility of not paying attention to the plant. However, when we plant a young specimen we remind to water the soil every time it dries completely, from April to October, and we also supply a slow release granular fertilizer every 4-6 months.
Since it is a creeper we remember to prepare a support for our new wisteria, like a pergola or a trellis, remembering that even a young plant will develop rapidly; therefore we consider a support that widens for at least a few meters, even if our wisteria looks small and thin.
Generally, the wisteria does not require other treatments, except for pruning, which allows us to keep the plant tidy and to obtain better blooms. The first pruning is practiced in late winter, when the buds are already clearly visible on the plant; it begins by removing all the branches ruined by the cold, or excessively thin; basal suckers and branches grown in the wrong direction are removed, then all the branches are shortened leaving only 3-5 buds on them.
Being a very vigorous plant it is often necessary to practice a high pruning in late summer, shortening all the thin branches, and also the old branches, by at least a third.
Remember that most of the wisteria present on the market are obtained by cuttings or grafting, so they should flower after about a couple of years after they are planted, even if well-bred plants bloom already during the first vegetative season. Sometimes we can also find plants obtained from seed, these often bloom only after 5-9 years after sprouting from the seed, so it may happen that our wisteria produces for many years only foliage and no perfumed bunches; if we do not want to be patient, let us be sure that the new plant does not come from seed, while we are still at the nursery and we are choosing it.
Wisteria can be grown espalier, but also in a fan, as a tree or as a semi-formal wall shrub. The initial pruning will therefore differ according to the final appearance desired.
In general, however, it can be said that it is important to lead the main stems horizontally to encourage flowering
To obtain an espalier specimen you need:
The first year prune the jet stronger after the implant by cutting it up to 75-90 cm from the ground. It must then be tied to a support. Cut all the other jets up to the base and remove all the side jets on the main jet to encourage new growth.
Later it will bind the main jet vertically as it grows in the summer. You will have to choose the two strongest side jets and cordurle them at 45 degrees. The secondary jets on the side ones will be cimed up to 15 cm in addition to removing all the growth at the base and the other remaining jets.
In winter the main jet is cut up to about 75 cm above the highest side jet. They will lower the side grooves which were at 45 degrees and will bind them horizontally by tying them to the supports and then cutting them by about 1/3.
|Family and gender|
Fabaceae, gen. Wisteria, 6 species
|Type of plant||Deciduous climber|
|Rustic||Rustic, some very rustic|
|Height and width||More than 9 meters in both directions|
|Composting||The first complete years, then based on potassium|
|colors||Lilac, white, pink||Flowering||From April to September, with different continuity depending on the species|
The botanical name of this plant refers to a German professor, Caspar Wistar, who taught at the University of Pennsylvania in the early nineteenth century. Previously, instead, it was given the name Glycinia, which from the Greek means "sweet" and from which derives the name usually used in Italian. Most of these plants are native to the Orient, China and Japan. However, there are also species from the United States. The first to be discovered was W. fruticosa: it arrived in England in 1724, was successful until the Asian varieties were introduced which produced a more abundant, continuous and showy flowering. The W sinensis was described for the first time in 1723, but his knowledge became more detailed starting from 1812. In fact, in that year John Reeves, being in Canton, asked a merchant to multiply the plant for him for the purpose of introduce it in Europe. The first specimens arrived in England in 1816: one of these first plants is still alive and can be admired in Kew Gardens.
Virtually all wisterias are very rustic and throughout Italy should not have any particular problems. Some, like the floribunda, are even more resistant and are therefore recommended in Northern Europe or in alpine areas. However, it may be a good idea to protect the plants during the first winter with a good mulch composed of flour manure, leaves and other insulating material for the roots.
W. are very tolerant plants and can grow well in almost all soils. To give a good flowering it is clearly better to prefer a soil rich in humus and good texture. However he does not disdain even poor or stony soils.
The only substrate to be avoided (or in any case improved) is the calcareous one: in fact (as we shall see) the wisteria is very subject to leaf chlorosis and having roots in an environment with a very high pH can only aggravate the situation, making the plant weaker and less floriferous.
The ideal position and that will allow us to get more satisfaction is in full sun. Only with a lot of light and heat it is possible to obtain glorious, abundant and continuous blooms.
Wisteria, however, tolerates even half shade and shade well without suffering too much. The most immediate consequence, however, will be a noticeable decrease in the blooms which, first of all, will arrive later. Secondly, the flowers will be more scarce.
Irrigations are very important during the first two years of planting, when the plant is not yet completely franked and therefore needs to be supported. It is therefore necessary to intervene weekly with an abundant distribution of water, especially in the absence of atmospheric precipitation. After this period the root system should have developed sufficiently to allow the subject not to suffer even in the absence of prolonged rains. This does not prevent us, of course, from intervening sometimes, especially during the summer and if we live in a particularly hot and dry area.
For the first two or three years, a good granular fertilizer should be distributed twice per vegetative period (in spring and at the end of summer), including all the macroelements and support minerals.
Starting from the second year, however, it will be good to start gradually reducing the amount of nitrogen and then using a product where potassium is absolutely prevalent.
This is because wisteria is part of the fabaceae family and like all leguminous plants it is able to fix the nitrogen present in the air in the soil thanks to a symbiotic relationship with some bacteria at root level.
During the first few years it will therefore be a good idea to contribute at least in part to the contribution of this nutrient more than anything else to favor a fast vegetative growth. Later, when the specimen has achieved a certain autonomy, our sole purpose will be to stimulate flowering at the expense of growth.
Wisterias are usually sold in small pots in the spring.
As with all shrubs, however, the ideal planting would be in the fall. In fact, in this way the plant has the whole winter to settle down and start producing new roots. This aspect is particularly important for a plant like the wisteria that needs at least two or three years from planting before starting to bloom. If we can, then, let's turn to a specialist dealer who will surely have plants available even in the months of October and November.
The process is quite simple. We need to dig a deep and wide hole at least twice the container. On the bottom it will be necessary to place a good quantity of manure, cornunghia or other organic soil conditioner. After having interposed a layer of earth separating from the roots, we can insert the plant (making sure that the roots on the bottom do not "tilt"), then covering it with some substrate and pressing well. Let us water abundantly. If the plant takes place before winter it will be good to cover the foot with plenty of flour.
Precautions on the choice of location and supports
Wisteria is a very powerful plant and you have to think carefully about where to place it in our garden to avoid any damage to buildings and plants.
The roots are able to reach pipes or infiltrate into foundations and then break them or (in the case of sidewalks) lift them. To avoid this inconvenience, you can surround the area with plastic that will prevent the hypogeum from leaving the area where it was intended.
Even the branches can be very powerful. Although initially they seem small and flexible with time they become woody and even very thick. They tend to wrap themselves with coils in a clockwise or counterclockwise direction (depending on the species), especially around the metal supports and then to bend them and tighten them inexorably. We therefore very well evaluate where to insert the plant and we follow its evolution carefully throughout the year. It is absolutely not advisable to make it follow the gutters because it would ruin them irreparably and is able to fit under the tiles to lift them with consequent serious damage to the house.
Pests and adversities
It is a very resistant plant and is rarely attacked by parasites or remains a victim of cryptogamic problems.
However, especially if the location is not particularly suitable or in the case of wet years it may happen that there are some drawbacks and therefore we give you a description.
Aphids: they are usually placed on apices or buds and suck the sap. Their appearance occurs in mid-spring. If the attack is not particularly strong, any intervention can be avoided. If, for example, the honeydew begins to appear and there is a serious aesthetic damage, you can intervene by distributing a specific insecticide, even if only by contact and ingestion.
Mites their appearance usually occurs during the summer, when the heat is very strong and there is a lack of humidity. The leaves take on a dry, bronze appearance and appear to be burned. Also here the intervention is not advised except in the case of severe debilitation of the specimen. At that time we can resort to specific acaricides, possibly with a translaminar action. If the infestations were recurrent it is advised during the winter to carry out a treatment with white oil activated by a specifically active acaricide against the eggs and the first stages of development.
Problems of cryptogamic origin: if the plant is very exposed to the sun and spring is very rainy it may happen that oidium traces appear on the leaves, characterized by a white patina that generally extends also towards the buds. If the problem is serious we can intervene with specific curative and eradicating products. If the condition is very common in our garden it is possible to intervene by distributing sulfur in powder or wettable.
Agrobacterium tumefascens It is a bacterium that affects the hypogeum, especially of plants of a certain age. Unfortunately once it is established it is impossible to fight. The only possibility to avoid it is to pay particular attention when we are able to and avoid any possible cuts in the collar area. Sprinkling with copper-based products, such as Bordeaux mixture, are also very useful after pruning.
Problems such as caries of the wood or various cancers can also be established. To avoid them, special care must be taken during pruning, using only well sharpened tools and disinfecting them before moving from one plant to another. The distribution of cupric is always useful.
If it were to manifest itself we could intervene with very sharp instruments and eliminate the infected parts up to a healthy area and place a specific anticryptogamic product on them. They are operations that require a certain amount of manual work and if we have a copy of a certain value it is better to ask the help of a professional.
This problem occurs rather frequently with wisteria. As we have said, this does not like the strongly calcareous soils because the roots struggle to absorb the iron present in them. The consequence is the discoloration of the leaves due to lack of chlorophyll. This not only has aesthetic consequences, but also functional ones, in fact the plant will surely grow and bloom less. To prevent this problem, 50-100 g of iron sulphate per square meter can be distributed at the end of the winter. If the problem is very serious we can also intervene with products based on chelated iron. However, they are all useful methods just for dabbing. The ideal would be to replace the substrate depth with a more acid one.
Pruning for maintenance
The wisteria does not usually have difficulty in flowering even if it is not pruned. However, it is possible to have a greater number of buds by making cuts regularly: one must intervene in late summer and then in winter with the aim of encouraging the production of new flowering branches.
In late summer all the growth of the current season is pruned up to 15-30 cm (unless you want to make the branches lengthen further. From the pruned jets other growth should appear and at the base of the jets the flower buds will form: compared those with wood (pointed and thin) are more rounded.
In late winter it is possible again until the two or three lower groans of the main branch.
If you find yourself with a neglected wisteria it will be good to intervene to give it order, vigor and abundance in the blooms again. In any case, the interventions will be distributed over several years.
In winter the main branches will be chosen damaged or old and will be cut up to the base. You will have to prune drastically to stimulate new vigorous growth. Unfortunately with this type of intervention there is often a reduction in the blooms for two or three seasons. We may, however, later enjoy a totally restored specimen.
Why doesn't my wisteria bloom?
This question occurs frequently.
Very often the problem comes from the plant's roots. Experienced growers reproduce the wisteria by grafting them onto vigorous specimens of Wisteria sinesis. This is the basis of a rapid growth and an equally fast arrival of maturity with consequent abundant blooms. Plants born from seed or from cuttings may also need 10 or 15 years before flowering.
The advice is therefore to buy only plants that have been previously grafted.
Another reason for the poor flowering comes from the incorrect fertilization, often too nitrogenous. After the first few years, as we have already said, it is preferable to use only products with a lot of potassium (for example granular fertilizers for tomatoes are good).
It is also very important to stimulate flowering a regular and reasoned pruning.
Wisteria - Wisteria: Wisteria variety
Wisteria sinesis It is native to China and can reach 10 meters in height. It flowers, between April and May, before putting the leaves. It is a woody, climbing trunk plant with pinnate leaves and composed from 7 to 13 long, elongated leaflets, 4 to 8 cm long, first covered with a thin down, then hairless. It produces blue-violet flowers (in the species), perfumed, gathered in bunches 15-30 cm long.
Wisteria floribunda originally from Japan, it flowers between May and June: it is a woody climbing plant with pinnate leaves composed of 13-19 leaflets from ovate-elliptic to ovate-elongated. The flowers are violet or blue about 2 cm long in shorter bunches than in sinesis. It is more rustic than this and loses the leaves first.
There are many cultivars: pink, white and purple, even with double flowers. The macrobotrys has very long clusters and is very valuable.
Wisteria frutescens: of American origin, more contained and more suitable for small gardens. It blooms starting in June.
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Wisteria, commonly known as wisteria, is native to the Far East and more accurately than China
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