Wisteria

Wisteria has a lot of big and beautiful flowers, so this plant is in almost every country that has warm weather. Wisteria is a genus of about 10 species,classified in the division of Magnoliophyta. They have vigorous, woody and twining vines which spread over the landscape. They usually can be found on stream banks in China, Japan, Korea, and the southern USA where they reach to 10 meters in height or more. If there is anything that can support it, it will grow in a clockwise spiral. Their leaves are alternate and are about 15-35 cm long. The flowers of the wisteria are produced in dangling racemes. It was named by Caspar Wistar(1761-1818). This flower is poisonous and consuming two seeds can kill a child. 

Anatomy
Wisteria typically are grown in home gardens. There are two types Wisteria; sinensis or Chinese wisteria, and Wisteria floribunda or Japanese wisteria. Wisteria is an aggressive and strong plant. It can spread easily, but American Wisteria spreads more slowly through seed production though the seedlings have high vigor. Wisteria can grow more than 65 feet in length, and they climb other plants or buildings by twining their stems. Their leaves are alternate, growing 15 to 35 cm long. This plant flowers in spring in the Asian species, while the American species flower in late summer. The leaves are pea-like, and they have different colors; purple, violet, pink or white.

The leaves have a crack in the middle and are compound. Japanese and Chinese wisteria grow about the same way as the American variety, but Japanese wisteria has a violet-blue color, and is stronger and bigger than any other wisteria. The flowers of wisteria open from the base of the cluster that is on the tip. Since this plant grows like a vine, this plant needs something that can support it as grows. For example, the plant will crawl up to a building or stick. Some of the Wisteria species have a fragrant smell, especially the Chinese Wisteria. The fruit of Wisteria is a long, green pod, which is not particularly ornamental. 

Reproduction
The reproduction is both sexual or asexual by layering of stems, which can produce roots. Even though their colors look like purple or bluish-purple, they are mostly like white-flowered form. They can be propagated by softwood cutting, hardwood cutting, and seeds. But seeded specimens can take a long time to bloom, so gardeners help it to grow. The other reason for failure to bloom is excessive fertilizer. Wisteria has nitrogen fixing ability. Flowering starts in April, before the Native American wisteria does, and their seeds may be transported through water. Most appearances of non-native wisteria seem to be the result of the persistence and vegetative spread of former plantings, although, seed propagation is also possible. Wisteria might not bloom, because it hasn't reached maturity yet. Maturation could be only few years for Kentucky Wisteria, but takes nearly twenty years for Chinese wisteria to fully grow. It can be forced to grow by physically abusing the trunk.

Ecology
Wisteria is a famous ornamental landscape plant. They are mostly located in the Eastern United States and East Asia, such as China, Japan, and Korea. However they can be found in Maine, Florida, and Arkansas. The world's largest Wisteria vine is located in Sierra Madre, which is in California. Its weight is 250 tons and it takes up more than an acre. This plant can grow fairly well in poor quality soil, but prefers moist, well-drained soil. Wisteria is very strong and fast growing. Chinese and Japanese varieties are adopted by the horticultural industry, because their inflorescence is larger and more active than other varieties. The native species grow from Florida to Virginia. As it was explained above, Wisteria needs something that can support it because it has many leaves and the stem. It could grow without any support, but it can't grow faster or stronger in that mode. So Wisteria can be found on other plants that can support wisteria, and some buildings. Chinese Wisteria can be found in provinces of China, such as, Guangxi, Guizhou, Hebei, Henan, Hubei, Shaanxi, and Yunnan. 

Other
Wisteria is an invasive plant, and there are many of them in some areas of the eastern United States, where the weather is similar to China. Wisteria, as an invasive plant, needs extra lookout by gardeners, since Wisteria is very poisonous. Anyone who needs to come close to it must be very careful.