Chinese wisteria (Wisteria sinensis) is a deciduous perennial vine with a twining growth habit. Like all members of the wisteria group, Chinese wisteria is a stunning bloomer. From May to June, it bears large, drooping clusters of fragrant flowers that are typically a bluish-purple. The vine is a vigorous climber that can grow to 25 feet. Trellises and other supports must be sturdy to hold the plant's weight. Chinese wisteria can take up to 20 years to mature enough to produce flowers. But it also tends to be very long-lasting, living up to 100 years.
|Botanical Name||Wisteria sinensis|
|Common Name||Chinese wisteria|
|Mature Size||10 to 25 feet long with a 4- to 8-foot spread|
|Sun Exposure||Full sun to part sun|
|Soil Type||Humusy, medium moisture, well-draining|
|Soil pH||Slightly acidic|
|Bloom Time||May to June|
|Flower Color||Bluish-purple, mauve, white|
|Hardiness Zones||5 to 8|
How to Grow Chinese Wisteria
When planting this vine, pick a spot where you can fit a solid support structure, such as an arbor or a pergola, that will be able to carry the weight of the plant once it's mature. To train wisteria vines, choose a single upright stem to attach to your support. Then, religiously remove any side shoots as they appear, forcing the plant into upward growth. Pruned correctly, the wisteria will form a beautiful overhead shade canopy. Once the plant reaches the height you want, continuously prune the tips of the plant to stunt further growth.
If you have trouble getting the vines to flower, there are several methods you can use. For instance, you can apply a high-phosphorus fertilizer, which can promote blooming. You also can try heavily pruning the plant right after it blooms and again in the winter to encourage more buds.
Many wisteria species prefer lots of sun, but Chinese wisteria can tolerate some shade. However, the best flowering occurs when the plant gets partial to full sun.
Chinese wisteria likes humusy, moderately fertile, and slightly acidic soil. Good drainage is key for the plant. Make sure the soil in your growing site fits the bill for this plant because it dislikes being transplanted.
Water a young plant deeply and frequently to help develop its root system, though you should never allow it to sit in soggy soil. Once established, the vine prefers even moisture via rainfall and regular watering, but it can tolerate a little drought.
Temperature and Humidity
Chinese wisteria can withstand temperatures down to around minus 20 degrees Fahrenheit. But its buds might die in prolonged cold, causing the plant to flower less. This plant likes high humidity but can grow in drier climates as long as its soil remains moist.
Fertilizer usually is unnecessary for Chinese wisteria unless your soil is deficient in nutrients. A layer of compost can be an effective way to promote growth and blooming.
Arguably the most high-maintenance part of caring for Chinese wisteria is its pruning needs. It requires regular pruning to maintain its shape and keep its growth in check. In fact, in much of North America the plant is regarded as an invasive species due to its ability to spread with vigor. Chinese wisteria sends out runners that can quickly overwhelm nearby plants and structures.
Prune your wisteria plant in the late winter, removing at least half of the previous year’s growth. Leave a few buds on each stem. You may prune it again just after it flowers in the late spring or early summer to clean up the plant’s shape. Trim off any dead or diseased growth as you spot it. If you cut back a mature plant too far, it should sprout again without issue. But those new sprouts might take several years to flower.
All parts of the plant contain a toxin known as wisterin. This can cause nausea, vomiting, diarrhea, dizziness, and confusion in humans and animals. Symptoms range from mild to severe depending on how much they eat. The seeds are especially dangerous because they have a high concentration of the toxin. So it's best to keep pets and children away from this plant.
Varieties of Wisteria
Two closely related species are Japanese wisteria (Wisteria floribunda) and American wisteria (Wisteria frutescens). Like Chinese wisteria, the Japanese species is known to be invasive in North America. Its flowers are considerably more spectacular, and it requires more sun than Chinese wisteria.
American wisteria is a smaller species, growing only two-thirds as long as the Chinese and Japanese species. Although its flowers are less showy, American wisteria blooms at a younger age than Chinese or Japanese wisteria. The American variety is recommended for landscape use because it is much less invasive. It's found naturally in the southeastern U.S. and a handful of other states.