According to the ancient legendary novel "Talking about the River", after Yang Di ascended the throne, he ordered the excavation of Tongji Canal. Yu Shiqi suggested planting willows on the embankment. Yang Di thought this suggestion was very good, so he ordered to plant willows on both sides of the newly opened Grand Canal and planted them himself. The imperial book named Yangliu as the surname and enjoyed the honor of sharing the surname with the emperor. From then on, the willow has the reputation of "willow". Willow gets its name from the working method of willow head wood. Wood is still an indispensable material. In ancient times, tools were very simple, so it was very difficult to cut thick trunks, but it was convenient to cut branches two inches thick. Therefore, the wood used by ancestors was mainly branches two inches thick. In the long-term use, people will find that after cutting off the branches, new branches can grow at the stubble, and the new branches are straight, which is more conducive to use. Among the native tree species in China, the ability of sprouting branches of willow is the most outstanding. Therefore, the first wood operation of willow was formed, and the crown was cut off at a certain height to promote the germination of new branches, and the branches were cut off every few years for use. The result of the first wood operation is to keep the trunk so as to continue to use the branches. This is why the willow tree got its name. The word "Liu" has the same pronunciation as the word "Liu", which means "Liu", which means a tree that keeps its trunk for reuse.

Willow is a general term for plants. There are many kinds of willows. Is it easy? Hybrid has great growth potential, strong adaptability and easy asexual reproduction. You can choose from natural or artificial hybrid populations and obtain excellent clonal varieties through asexual propagation. In addition, a large number of high-quality seedlings can be obtained quickly by plant tissue culture. Breeding based on ornamental gardens should focus on improving their branches, leaves and tree shapes, and improving their anti-pollution and pruning and shaping abilities. Used for garden viewing, residential areas, gardens, schools, factories, hillsides, courtyards, roadsides and buildings. When in full bloom, the branches spread out to the willows, making the courtyard full of green with high ornamental value; It is an ideal tree species to beautify the courtyard. Willow is also one of the tools for people to enjoy the cool, especially in the summer afternoon, people go to look for a good place to enjoy the cool in twos and threes. At this time, the shade of huge willows is a unique choice for people. In spring, willow is the most charming and chic tree, and it is also one of the themes praised by poets and writers for thousands of years.

Morphological characteristics: willow branches are slender and drooping, brownish green and hairless; Winter buds are linear and close to branches. Leaves alternate, linear-lanceolate, 7- 15cm long and 6- 12cm wide, with sharp ends, serrated edges with small glands, dark green surface, gray-white back, smooth and hairless on both sides, and stipules. After the leaves bloom, the male inflorescence is a short peduncle, slightly curved and 1- 1.5 cm long. The fruit is a capsule with 2 petals at maturity, containing many seeds with a tuft of hairs on them. Cutting propagation has strong resistance to air pollution and dust, and is suitable for growing in urban gardens, especially in pools or streams. The leaves are linear-lanceolate or narrowly lanceolate, about 6~ 14cm long and 5~ 12mm wide, with fine serrations at the edges. Flowers bloom from April to May every year, with male inflorescences 2~4cm long and female inflorescences about 2cm long. The general name of Salix plants in Salicaceae. More than 520 species, 257 species from China, 120 variety, 33 varieties. Deciduous trees or shrubs, bud scales 1, dioecious, stamens 2, 3, 5 or many. Capsule, 2-lobed. Mainly distributed in temperate regions of the northern hemisphere. The main tree species are Salix Salix (height about 20m, DBH 80cm), Salix weeping willow (height about18m) and Bai Liu (height about 30m, DBH1.5m).

Growth habit: Willow is a kind of plant with ecological amplitude, which has wide adaptability to the environment. Light-loving, wet-loving and cold-resistant, it is a medium-sized wet tree species. However, some species are also more drought-tolerant and salt-tolerant, can grow in places with poor ecological conditions, and grow better in plain areas with excellent site conditions. The average life span is 20 ~ 30 years, and a few varieties can reach 100 years or more. The annual growth period is long, with early germination and late defoliation, and individual tree species in the south are evergreen trees.