The Latest Cultivation Techniques and Methods Tutorial for Osmanthus Saplings

The osmanthus has lush foliage and is evergreen, with a long lifespan; it blooms in autumn and is richly fragrant. It is an ornamental flowering plant and fragrant tree native to China. The areas in China where osmanthus is concentrated and cultivated are mainly the vast tropical and northern subtropical regions north of the Nanling Mountains and south of the Qinling Mountains and Huaihe River. Osmanthus trees are quite popular in home cultivation. Below, the editor of Qiannong Network will introduce the cultivation techniques for osmanthus saplings!

Selection of the Cultivation Environment for Osmanthus Saplings

Osmanthus trees prefer a warm and humid climate. They tolerate high temperatures but are not very cold-hardy, being a subtropical tree species. Osmanthus is not very demanding about soil. Apart from alkaline soil, low-lying land, or soil that is too heavy and poorly drained, it can generally grow in most soils, but deep, loose, fertile, well-drained, slightly acidic sandy loam is more suitable.

Osmanthus is best grown in deep, well-drained, fertile, humus-rich, slightly acidic sandy loam. It is not tolerant of drought or barren conditions. In shallow, compacted, poor soil, it grows especially slowly, with sparse branches and leaves, small thin leaves, and yellowed leaf color; it does not bloom or blooms very little, and may even show periodic dieback of the top, with the entire osmanthus plant dying in severe cases.

Osmanthus likes sunlight but has a certain shade tolerance. Young trees need some shade, while mature trees require relatively ample light to ensure normal growth. Observations show that when one side of a single osmanthus tree's canopy is close to a wall, or when the canopies of two osmanthus trees overlap each other, the side close to the wall or the overlapping part of the canopy quickly becomes sparse, affecting the overall shape and beauty of the canopy. It can be seen that osmanthus is suitable for planting in ventilated and well-lit places. Osmanthus likes a clean, ventilated environment and is not tolerant of smoke and dust damage; after being harmed, it often fails to bloom. It is afraid of waterlogging and standing water. If harmed by waterlogging, the root system turns black and rots, the leaf tips first scorch, then the entire leaves turn yellow and fall off, eventually leading to the death of the whole plant.

Propagation Techniques for Osmanthus Saplings

Osmanthus propagation and seedling-raising methods include cuttings, layering, grafting, and sowing, with cutting propagation being the main method.

1. Cuttings: Cutting is generally done in June-July or September-October, and sandy loam is suitable for the cutting bed. Use semi-mature branches of the current year as cuttings, with terminal branches being the best. After cutting, shade promptly, water thoroughly, and strengthen water and fertilizer management. Generally, healing begins 20 days after cutting, and rooting occurs in 30-40 days. Cold protection measures are needed in winter, and the following year the seedlings can grow to about 30 cm tall.

2. Layering: Layering is divided into air layering (high layering) and ground layering, and can be done in all four seasons. The air layering method is carried out in early April, while the ground layering method is best done in early April or during the plum rain season. When layering, wounding or ring-barking is required, and after 1 year it is separated from the mother plant. For ground layering, the buried depth of the layer is about 4-5 cm, and the more curved the buried part of the branch, the better.

3. Grafting: Grafting propagation is done in March-April. The rootstock is mostly small-leaf privet or large-leaf privet. The grafting method is stem grafting; cut grafting, cleft grafting, and approach grafting are all acceptable. During grafting, shade is required and moisture should be maintained. For cut grafting and cleft grafting, the graft union should be as low as possible; generally the rootstock is cut off at 3 cm above the ground. After tying, mound soil up to the top of the scion so that it may possibly root from the scion part, improving the survival rate.

4. Sowing: Sow in winter or early spring, in drills, with a row spacing of 15-20 cm, sowing 30-40 seeds per meter, with a sowing rate of 8-10 kg per mu, covering with humus soil or burnt soil about 1.5 cm thick, and then covering with grass. Generally, germination begins 40-50 days after sowing and can continue for up to 50-60 days, with very uneven germination. July-September is the period of vigorous seedling growth, so attention should be paid to topdressing and drought resistance. One-year-old seedlings can be released from the nursery when they are more than 30 cm tall.

5. Seedling release from the nursery: After layered seedlings and grafted seedlings have rooted, they can be planted in winter or set out in the nursery to cultivate large seedlings. Cutting seedlings more than 30 cm tall, sowing seedlings more than 25 cm tall, and with a ground diameter of more than 0.4 cm can be released from the nursery for afforestation or transplanted to a large-seedling cultivation area. When lifting seedlings, keep the root system as intact as possible; after lifting, plant them promptly, and if long-distance transport is needed, pay attention to moisture retention.

Pest and Disease Control for Osmanthus Saplings

1. Scale insects

① Combine with manual pruning to scrape off and remove overwintering pests.

② Before the tree sprouts, spray 5% anthracene oil emulsion or 5-degree lime sulfur mixture.

③ When scale insects first appear and have not yet formed a waxy layer, spray malathion 1000-fold solution or 25% imidophos emulsifiable concentrate 1000-fold solution, which gives relatively good control results.

2. Red spider mite: It mainly sucks nutrients from osmanthus buds, leaves, and flowers, causing osmanthus buds and flowers to dry up and making branches and leaves turn yellow or wither. Spray 3-5 degrees Baume lime sulfur mixture before sprouting, or spray 0.3-0.5 degrees Baume lime sulfur mixture before and after flowering.

3. Leaf spot disease: It mainly harms leaves, and in severe cases causes leaf drop. In high temperature and humid conditions, this disease develops quickly. In June-July before flowering, 0.5 kg of 80% mancozeb wettable powder can be mixed with 250-300 kg of water for spraying as prevention. During the growing season, depending on the condition, a 1:1:100 equal-strength Bordeaux mixture can be sprayed.

4. Rot disease: It mostly occurs on large trunk branches and branch crotches. Control measures: strengthen fertilizer and water management, enhance tree vigor, and improve drought resistance and disease resistance; after onset, scrape and treat promptly. According to the disease pattern, the focus of inspection and scraping treatment should be in early spring and autumn; after scraping, applying 5-degree lime sulfur mixture gives relatively good results.