Ginkgo biloba was planted in the south of the Yangtze River during the Three Kingdoms period at the end of Han Dynasty. According to records, there was a kind of Ginkgo biloba in the Tang Dynasty, which was more common in the Song Dynasty and was introduced to Japan.
Later, Ginkgo biloba was spread from Japan to Europe and America, and now it is cultivated in more than 50 countries in the world.
Ginkgo biloba is a famous street tree, street tree and garden tree, with majestic posture, golden autumn leaves and few pests and diseases.
Suitable for planting in gardens, parks, roads and scenic spots, often planted in temples and places of interest, and also a good material for making bonsai.
Ginkgo biloba is a deciduous tree with an oval crown.
Fan-shaped leaves are solitary on long branches or clustered on short branches, shallowly lobed, with parallel veins, 6-8 cm long, light green surface and golden yellow in autumn.
Dioecious, less common, female branches open or droop slightly, leaves are thin and shallow, male plants are tall and erect, and leaves fall late.
Flowers bloom from April to May.
The fruit is spherical, yellow, 1 1 month mature.
Common varieties are: tower-shaped ginkgo biloba with inclined branches and a cylindrical or steeple crown; Ginkgo biloba has drooping branches, drooping branches; Ginkgo biloba leaves, large leaves, deep cracks; Ginkgo biloba with macula; Ginkgo biloba with yellow leaves and bright yellow leaves.
Ginkgo biloba is a positive tree species, which likes light and is not tolerant to shade.
I like deep, fertile, loose, moist and well-drained soil, which has a wide range of pH adaptation and can grow well at pH 5.5 ~ 8, but it is not resistant to stagnant water.
Strong cold tolerance, can grow normally at -20℃, and can also adapt to high temperature and rainy climate.
Tree species with deep roots have developed roots and are not afraid of strong winds.
Ginkgo sprouts in early April and spreads its leaves in mid-April. The growth peak of new shoots is from May to June after flowering, and it stops growing in July and August. After autumn, it turned into thick growth, and stopped growing from September to 65438+1October when the seeds matured. At the same time, the leaves began to turn golden yellow, and the leaves fell from 1 1 to 65438+February, with an annual leaf age of about 240 years.
There are obvious differences between the short branches and the long branches of Ginkgo biloba.
The top bud of the long branch and several buds near the top still grow into thick long branches every year, and the middle bud grows into slender branches or short branches; The terminal buds of short branches continue to form short branches or differentiate into flower buds, and the life span can reach more than 10 years.
The growth of long branches in each year is easy to distinguish, but short branches are not easy to distinguish.
Ginkgo biloba has good natural tree posture, strong germination ability, many latent buds and long incubation period.
The apical dominance of male plants is more obvious than that of female plants, and the branching angles of female plants and male plants are also different. The female plant is larger and the branches are stretched. The male plant is small and the branches stand upright.
When shaping and pruning, it should conform to its natural tree shape.
The male plants that are sown and propagated are all shaped by the central leadership. Because their main branches have a small opening angle, they should try to choose the ones with a large opening angle when choosing skeleton branches to make the tree look more majestic.
The female plants that are sown and propagated adopt the shape of central leadership trunk or multi-leadership trunk, but the opening angle of skeleton branches should not be too large to avoid being overwhelmed when they grow up.
Because of the slow growth of Ginkgo biloba, the height of 2-3-year-old seedlings is only about 1 m. It takes more than 6 years (generally 2.5-3 meters) to determine the plastic belt by the above two methods, but it is easy to form and usually does not need a lot of pruning.
When selecting and retaining new auxiliary branches every year, cut off the lowest auxiliary branches, and make some appropriate arrangements because of the different tree shapes of male and female plants. Common methods are thinning and medium and short cutting. Thinning is mainly aimed at miscellaneous branches, and medium and short shears are generally used to change the branch angle. Pay attention to keeping suitable cutting buds.
Generally, the grafted Ginkgo biloba is mainly female, with high subcutaneous grafting, plastic belt as the grafting site, and three grafted branches with large angles.
This kind of grafted ginkgo biloba is reshaped by leaderless trunk.
The main purpose is to prevent its main branches from extending outward without restriction, and to avoid the growing load on each main branch with the growth of trees, which leads to the unbearable burden on the grafting parts.
Therefore, it is necessary to use medium-short cutting and choose cutting buds that can fill the gap in the crown. When there are too many branches, they should be properly sparse.
Seedling raising and maintenance and pruning of Ginkgo biloba are carried out in winter, with maintenance and pruning 1 time every year, and competitive branches, dead branches and drooping aged branches are cut off, so that there are more short branches and fewer long branches.
Ginkgo biloba has a long life and well-developed cryptobuds, so it can be re-cut and updated.