What is the growth and development law of osmanthus trees?

Morphological characteristics: osmanthus trees are elegant, with green branches and leaves, evergreen seasons and pleasant fragrance. Osmanthus fragrans is an evergreen broad-leaved tree with a height of15m and a crown of 400 square meters. Osmanthus fragrans seedlings have obvious taproots, developed and deep roots. Young roots are yellow-brown, and old roots are yellow-brown. The root system of grafted seedlings varies with rootstock; When cuttings are buried in the soil, adventitious roots grow everywhere, but there is no obvious main root. Osmanthus fragrans has strong branching and low branching point, especially in its infancy, which often appears as a shrub for a long time. After close planting or pruning, it can become an obvious trunk. Bark rough, gray robe color or gray white, sometimes showing lenticels. The leaf surface is smooth, leathery, the paraxial surface is dark and bright green, and the distal axis is pale; Oval, oblong, ovoid, obovate, lanceolate, oblanceolate, oblanceolate to ovoid.

Usage: Osmanthus fragrans is evergreen all the year round, with lush foliage, blooming in autumn and overflowing fragrance, which can be described as "monopolizing Sanqiu over others". It is widely used in gardens, often used as landscape trees, including single planting, opposite planting and cluster planting. In the classical gardens of China, osmanthus flowers are often matched with buildings, mountains and rivers, and stone machines, and shrubs are planted near pavilions, terraces, buildings and pavilions. Old-style gardens are often planted relatively, which was called "double laurel in the court" or "double laurel leaves fragrance" in ancient times. Planting osmanthus trees around the house or in front of the window can get the effect of "golden wind sending fragrance". Osmanthus fragrans is resistant to harmful gases such as sulfur dioxide and hydrogen fluoride, and it is also a good greening flower in industrial and mining areas.

Habit: Osmanthus fragrans is an evergreen shrub or small tree of Oleaceae, with a height of 1.5 ~ 8m. Crown is round head, semicircle and ellipse. Leaves opposite, leathery, inflorescence clustered in leaf axils. The flowering period is from September to 10 and the fruiting period is from March to April of the following year.

Osmanthus fragrans adapts to the vast subtropical climate. Sexual preference is warm and humid. The average temperature in the planting area is 14 ~ 28℃, the average temperature in July is 24 ~ 28℃, the average temperature in June is above 0℃, the minimum temperature is-13℃, and the optimum growth temperature is 15 ~ 28℃. Humidity is very important for the growth and development of osmanthus fragrans. The annual average temperature is 75% ~ 85%, and the annual precipitation is about 1 1,000 mm. Especially when young trees and adults bloom, they need more water. If you encounter drought, it will affect flowering, and strong sunlight and shade are not good for its growth. Generally, they need 6-8 hours of light every day.

Planting: Osmanthus fragrans does not require much soil and water. The soil should not be too wet, especially to avoid water accumulation. In case of waterlogging, the roots rot and leaves fall off, resulting in the death of the whole plant. There are certain requirements for air humidity. Poems by famous people in ancient China, such as "the mountain is beautiful before the fog is thick" and "the mountain clouds are lonely and osmanthus is wet", vividly illustrate that osmanthus flowers need a foggy and wet condition with clear day, cool night and moist rain and dew.

Osmanthus fragrans leaves are dense and need to consume a lot of nutrients. It is suitable for growing on sandy loam with deep soil layer and rich humus, and can also grow normally on cohesive soil. But it can't tolerate dry and barren soil, otherwise it will grow very slowly, its leaves will turn yellow generally, and even its top will wither periodically. It is suitable for growth in slightly acidic soil with pH 5.5 ~ 6.5, and alkaline soil will lead to physiological iron deficiency in osmanthus fragrans. Although the leathery leaves of osmanthus fragrans have a certain ability to resist smoke and dust pollution, after being polluted, there will often be a phenomenon that only leaves grow without flowering.

Growth and development law of osmanthus fragrans: In the Yangtze River basin, from late February to early March every year, osmanthus fragrans begins to shoot new shoots. Generally, new buds are 5 ~ 25 cm long, and some are as long as 40 cm or more. The investigation shows that all branches with flowering length less than 50 cm can form flower buds, which are easy to bloom, especially the branches with 5- 15 cm have the most flowers. Most of the hanging flowers of flower buds are located at the top node and its nearby nodes, and there are few flowers below the top bud to 6 nodes. The survival of flower buds is related to the age of branches. Generally, branches less than 8 years old can blossom, but the branches in the same year bloom the most. There are few branches and flowers for more than 3 years, and the production value is not great. Usually flowers bloom twice before and after the National Day, with an interval of about 2 weeks. The flowering period is often affected by air temperature and humidity: when autumn is humid and the temperature is low, the flowering period is earlier; On the contrary, in case of high temperature and dry weather, the flowering period will be delayed accordingly. According to the experience accumulated in Guangfu producing area of Suzhou for hundreds of years, the phenology of osmanthus fragrans can be divided into 10 stages: germination stage, pearl stage, top shell stage, boll stalk stage, fragrant eye stage, initial flowering stage, initial flowering stage, full flowering stage, late flowering stage and full flowering stage. The whole flowering process lasts about half a month from the pearl stage when the buds are obviously enlarged to the withering flowering stage. The best viewing period with ornamental value is about 5-6 days, while the best harvesting period of flowers is only 2-4 days.

Osmanthus fragrans has a long economic life. Take the main variety "Russian Yinjia" in Suzhou Guangfu production area as an example: it begins to blossom after 5 years of planting, and it will be put into production after 10 years, with 0.5 kg of flowers per plant; Can receive 4-5 kilograms of flowers at the age of 20; 50-year-old flowers can receive 15-20 Jin; An 80-year-old man can collect 20-25 kilograms of flowers. As long as it is properly managed, it can still maintain a certain output until 200-300 years. This further shows that osmanthus fragrans is a garden tree species with high ecological, social and economic benefits.

Osmanthus fragrans fruits generally mature in April-May, and can be harvested when the peel gradually changes from green to purple-blue. After harvesting, water is sprayed for composting, pulp is removed, seeds are dried in the shade, and mixed with sand for storage. Hanging flower seeds have the function of post-ripening, and should be stored in sand for at least half a year until June 65438+1October of that year for autumn sowing or spring sowing the following year. According to the experience of Guilin, Guangxi, it is required that the sand layer is not wet at the initial stage of sand storage, and the water holding capacity of sand is 10%. In the middle and late stage of sand storage, the water holding capacity of sand can be gradually increased to 50% to ensure that most seeds in sand storage can germinate smoothly. During sand storage, attention should also be paid to prevent lightning strike and rodent damage to seeds. Sowing is usually carried out by drilling holes.