Chinese Wisteria (Wisteria sinensis)
the Chinese Wisteria (Wisteria sinensis) is the most vigorous type of the type Wisteria. It belongs to the papilionaceous family (Fabaceae) and is also known as wisteria. As its name suggests, Wisteria sinensis is originally native to China.
The (unlike the related Japanese blue-green) left-winding Chinese blue-green is extremely vigorous and can reach a final height of ten meters. Blue rain is one of the few climbing plants that develop such a stable trunk over the years that they are able to wear their crown without climbing aid. This is why you can also draw the deciduous blue rain as a tall stem with suitable pruning measures. Wisteria is long-lived and can live up to 100 years. All parts of the blue rain – especially flowers and fruits – are poisonous (also for many animals)!
The deciduous climbing plants have smooth, pinnate leaves with 7 to 13 narrow, egg-shaped individual leaves. The leaves turn yellow in autumn and are then discarded.
The Chinese blue rain offers an overwhelming spectacle during its heyday. The blue flower clusters are close together and can grow to over 30 centimeters in length. The single blue-violet flowers appear even before the leaves shoot in May. All flowers of a grape open at the same time. Occasionally it comes to a weaker after-flowering in the late summer. The nectar-rich and fragrant flowers are strongly flown by bees.
The fruits of the blue rain appear as green pods with a downy coat. The seed capsules, each containing one to three seeds, ripen in late summer, but usually do not empty until the following spring. With a casting distance of ten metres, the Chinese blue rain sows itself on a large scale
A sunny, warm and protected location, for example a south-facing house wall, is ideal for the blue rain. It also thrives in semi-shade, but does not bloom so abundantly there.
The climbing plant feels at home on all slightly damp, nutrient-rich and loose soils. The blue rain prefers slightly acidic ground and is very sensitive to waterlogging.
The correct planting time for blue rain is in spring or autumn. Normal potting soil mixed with some compost is sufficient as substrate for the climbing plant. Then water well and apply a layer of mulch to the planting area. After planting, it may take several years for the first flower to bloom. When planting blue rain, use very stable trellises that are well anchored in the soil so that the plant does not outline them over the years. Ropes with tendrils are not sufficient for the vigorously growing blue rain and are simply torn out of the wall over time. It is no longer possible to remove the climbing aid under the plant after a few years, as the climbing plant will fully bind to the scaffold over time. Attention: Do not place the plants on rainwater downpipes and make sure that they do not wrap around the gutters. The strong, winding shoots of the blue rain are able to crush even metal pipes and gutters with their thickness growth. Beware even of cracked plaster: it can be infiltrated by the blue rain.
As the blue rain is quite sensitive to drought, you should water the plant in good time during persistent heat, especially in spring before flowering, otherwise the blue rain will throw off the flower buds. Avoid nitrogen-rich fertilization, as the blue rain synthesizes nitrogen at the roots through nodule bacteria. Too much nitrogen leads to increased leaf and shoot growth at the expense of flowering. Tip: In order to reduce the strangling power of the blue-green shoots, it is advisable to unwind the young, flexible shoots annually from the climbing aid and guide them straight along it so that they can build up less pressure.
Two prunings per year are necessary to keep the strongly growing climbing plants in check and to ensure a lush flowering. The flowers appear exclusively on the lower buds of the side shoots, which is why they are rigorously reduced to three to five buds after flowering. In spring, the thin shoots newly formed after the first pruning are again strongly pruned. If a blue-green gene has not been cut or guided for several years, it is usually impossible to untangle the branches and twigs, but the plants can tolerate strong pruning and sprout from thicker stems. The best time for such a radical cut is the end of February. In the case of grafted specimens, wild shoots close to the ground must be removed at an early stage. Attention: If the pruning of the blue rain is neglected for some years, the thick shoots entwine each other and make further forming of the plant impossible!
Blue rain planted in autumn is grateful for winter protection in rough locations. Otherwise, the Chinese blue rain is hardy and does not need special protection when it is established. During strong frosts the young wood may freeze back a little. Care should be taken with late frosts, because then the whole flower can freeze to death in one night.
Due to its tendrilous growth and its umbrella-shaped crown, the Chinese blue rain is excellently suited as pergola or foliage planting. The climbing plant can also be mounted on a house wall, wall or stable balcony railing. Since the blue-green rain combines a very small planting area with exuberant flower splendour, it should be considered in any case for the greening of stable substructures. Wisteria are also very suitable for cultivation in attractive vessels, for example as stems with a compact crown. Choose a young plant with two shoots and a strong stem.
The Chinese blue rain ‘Alba’ forms white instead of blue blossom grapes in spring. The white flowers also have a light scent.
Blue rain should always be propagated by cuttings, since seedling propagated Wisteria carry a clearly reduced flower. Such plants usually only show their first flowers after more than ten years and never bloom as luxuriantly as grafted specimens. Due to the better growth and flowering properties, it is better to buy refined specimens in specialist shops.
Diseases and pests
In addition to classic pests such as spider mites and aphids, voles also like to feed on the roots of the blue rain. If vole problems are known at the site, the plant should be planted in a stable vole basket.
Whether fruit, vegetable and ornamental plants in the garden or indoor plants in the house: spider mites can infest and damage many different plants. Here René Wadas, a herbalist, will tell you his tips on how you can effectively fight the arachnids.Credits: Production: Folkert Siemens; Camera: Fabian Primsch; Editing: Dennis Fuhro, Photos: Flora Press/FLPA, GWI
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I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.