The Latest Osmanthus Tree Planting Techniques and Methods Tutorial
Osmanthus is an evergreen shrub or small tree of the genus Osmanthus in the family Oleaceae, also known as rock osmanthus, jiulixiang, golden millet, etc. It is an excellent garden tree species that combines greening, beautification and fragrance, with both ornamental and practical value. In ancient Chinese flower-themed poetry, the number of works praising osmanthus is also quite considerable, and it has been deeply loved by Chinese people since ancient times. Now let us take a look at osmanthus tree planting techniques!
Variety Classification of Osmanthus Trees
1. Four-season osmanthus variety: The four-season osmanthus is a clumping shrub with a low, short tree form, short and dense branches, and a round spherical crown. New leaves are dark red, while mature leaves are green or yellow-green. The leaves are elliptical to broadly ovate, with a very large angle between the main vein and lateral veins, approaching a perpendicular state. Flower buds are usually solitary or 2 to 3 stacked together, blooming in batches from September each year to the following March, with a fragrance less intense than that of silver osmanthus, golden osmanthus, and red osmanthus. Common varieties include large-leaf four-season osmanthus and small-leaf four-season osmanthus; varieties that bloom in all four seasons include Yueyuegui, Rixianggui, Daye Fodingzhu, and Ch'iye four-season osmanthus.
2. Red osmanthus variety group: Red osmanthus is dioecious, with a round spherical crown, light gray bark that is relatively smooth, and sparse lenticels. The leaves are leathery, long elliptical or elliptical, with a relatively flat leaf surface, revolute leaf margins, entire margins, occasionally with sparse teeth at the apex, a broad cuneate base, an obtuse or shortly pointed apex, 8 to 10 pairs of lateral veins, reticulate veins obvious on both sides, and a petiole 8 to 10 mm long. The flower color is orange-red, the corolla is slightly incurved, the fragrance is light, and the flowering period is from late September to early October. Varieties include Dahuadangui, Chidangui, Zhushadangui, and Kuanyehong.
3. Golden osmanthus variety group: The golden osmanthus has a round spherical crown, strong tree vigor, upright branches, and is very compact. The bark is gray, the lenticels are round or elliptical, and the spring shoots are relatively stout. The leaf color is dark green, the leaves are elliptical, the leaf surface is uneven, and the leaf margins are slightly wavy. The flower color is yellow, with a strong fragrance, and it does not set fruit. It blooms in autumn, with flowers ranging from lemon yellow to pale golden yellow. Varieties include Dahuajingui, Dayehuang, Huangchuan Jingui, Wanjingui, Yuanyejingui, Xianning Wangui, Qiugui, Yuanbian Jingui, Liuyesugui, Jinshigui, and Boyejingui.
4. Silver osmanthus variety group: The silver osmanthus has a round spherical crown, spreading large branches, dense branches and leaves, and good growth. The bark is light gray, and the lenticels are numerous and large, shaped like snowflakes, and very obvious. The leaves are green or dark green, long elliptical or elliptical, relatively broad and thick, with a relatively flat leaf surface. It blooms in early to mid-September, with flower color from creamy yellow to lemon yellow, a rich fragrance, and it does not set fruit after flowering. It blooms in autumn. Varieties include Kuanyezaiyingui, Liuyeyingui, Yingyeyingui, Zaiyingui, Jiulonggui, Zaoyingui, Wanyingui, Baijie, Chunbaiyingui, and Qingshanyingui.
Planting Environment for Osmanthus Trees
1. Temperature: Osmanthus trees prefer warmth. The average temperature in the planting area is 14 to 28°C, the average July temperature is 24 to 28°C, the average January temperature is above 0°C, it can tolerate a minimum temperature of -13°C, and the most suitable growth temperature is 15 to 28°C. In areas south of the Qinling Mountains and the Huai River in China, it can overwinter outdoors. It is not very cold-resistant, but compared with other evergreen broadleaf tree species, it is still a relatively cold-resistant tree species.
2. Water: Osmanthus trees prefer moisture. Humidity is extremely important for the growth and development of osmanthus. It requires an annual average humidity of 75 to 85% and annual precipitation of about 1000 mm. Especially during the young stage and when adult trees are flowering, it needs more water. If it encounters drought, flowering will be affected. It should never be waterlogged, but it also has a certain drought tolerance.
3. Light: Osmanthus prefers sunlight and can also tolerate shade. Under full sunlight, its branches and leaves grow luxuriantly and it blooms densely; in shady places, the branches and leaves are sparse and the flowers are few. If potted indoors in the north, special attention should be paid to ensuring sufficient light to favor growth and flower bud formation. Strong sunlight and deep shade are unfavorable for its growth. Generally, 6 to 8 hours of light per day is required.
4. Soil: Osmanthus is not very demanding about soil. Except for alkaline soil, low-lying land, or soil that is too sticky and heavy with poor drainage, it can generally grow. However, deep, loose, fertile, well-drained slightly acidic sandy loam is most suitable.
5. Air: Osmanthus has a certain resistance to harmful gases such as chlorine, sulfur dioxide, and hydrogen fluoride, and also has a strong ability to absorb and retain dust. It is suitable for planting in ventilated and light-transmitting places. It likes a clean and ventilated environment and is not resistant to smoke and dust damage; after being harmed, it often cannot bloom.
Propagation Techniques for Osmanthus Trees
1. Sowing: Osmanthus fruit usually matures from April to May. It can be harvested when the peel changes from green to purple-black. Osmanthus seeds have after-ripening; they need at least half a year of sand storage. After harvesting, sprinkle water and pile them for fermentation, remove the pulp, place them in a cool place to let the seeds dry naturally, and store them mixed with sand. After sand storage, they can be sown in autumn or spring. Before sowing, prepare the land well and apply sufficient base fertilizer; they can also be sown in indoor seedbeds. When sowing, place the seed hilum sideways to avoid bending of the radicle and young stem, which would affect seedling growth in the future.
2. Grafting: Osmanthus grafting rootstocks are mostly privet, small-leaf privet, waxleaf privet, water wax, etc. When propagating seedlings in large quantities, small-leaf privet is mostly used. Before spring sprouting, cut off the rootstock 5 cm above the ground. Cut 1- to 2-year-old strong osmanthus branches 10 to 12 cm long, cut one side of the base into a 2 to 3 cm cut surface, and cut the opposite side into a small 45-degree bevel. Make a vertical cut about 2 to 3 cm deep at about 1/3 of one side of the rootstock, insert the scion into the cut, align the cambium, tie it tightly with a plastic bag, and then cover with soil for cultivation.
3. Cuttings: Osmanthus cuttings are usually taken before spring sprouting using one-year-old fully developed branches, cut into 5 to 10 cm lengths, with the lower leaves removed and 2 to 3 green leaves retained at the top, inserted into river sand or loess seedbeds at a row spacing of 3*20 cm. After insertion, water or spray promptly, shade, maintain a temperature of 20 to 25°C and a relative humidity of 85 to 90%, and after 2 months they can root and be transplanted.
4. Layering: Osmanthus can be divided into low layering and air layering. The low layering method is to select relatively stout lower branches 1 to 2 years old from the lower part of a low-trunk mother tree in spring to early summer, choose an easily bendable part, cut or girdle it with a sharp knife, press it into a 3 to 5 cm deep trench, and fix the pressed branch with a wooden stick. The air layering method is to select 1- to 2-year-old stout branches from the mother tree in spring, cut a ring or girdle them as in the low layering method, then apply culture medium to the wound, tie plastic bags tightly above and below, and after rooting in autumn, cut them off from the mother plant for care.