How to Cultivate Golden Osmanthus Trees? Latest Technical Method Tutorial

Golden osmanthus is an evergreen broadleaf tree of the genus Osmanthus in the family Oleaceae. It has lush branches and leaves all year round, with golden-yellow flowers, beautiful yet not delicate, and a rich fragrance, subtly elegant without being showy. Among the many osmanthus varieties, it has the highest ornamental value, and its flower color, fragrance, and flower quantity are comprehensively superior, making it a favorite for introduction and cultivation in gardens across southern China, especially for ornamental cultivation. Let us take a look at the cultivation techniques for golden osmanthus trees!

Ecological Habits of Golden Osmanthus

Golden osmanthus is adapted to subtropical climate regions. It prefers warmth and humidity, can tolerate a minimum temperature of -13°C, with an optimal growth temperature of 15-28°C. It requires an average annual humidity of 75-85% and annual precipitation of around 1000 mm. It has strong stress resistance, prefers sunlight but can also tolerate shade. Under full sunlight, its branches and leaves grow luxuriantly and it blooms profusely; in shaded areas, its branches and leaves are sparse and flowers are few. It is not very demanding regarding soil. It can generally grow in any soil except alkaline soil, low-lying areas, or overly heavy clay and poorly drained soil. However, deep, loose, fertile, well-drained slightly acidic sandy loam is most suitable. It 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, so it is often used in cities and industrial and mining areas.

Propagation Techniques for Golden Osmanthus

1. Layering propagation: Usually at the end of March or beginning of April, around the mother plant, depending on the number of branches that can be layered, dig a small trench 20 cm deep and 20 cm wide along the natural direction of branch growth, then bend the branches down into the trench, fill the trench with fertile soil and firm it by stepping on it, water thoroughly, and then mound the soil at the layered position into a steamed bun shape.

2. Air layering: Usually between September and October, split a section of bamboo culm into 2 pieces, fill it with moist soil, and attach it to a robust branch of a superior osmanthus variety. Support it with a frame, add water regularly to keep the interior moist, and after more than one month, new roots will emerge. The following spring, remove and transplant it to form a osmanthus tree, which can bloom in about 3 years.

3. Seed propagation: Every year at the end of May or beginning of June, pick mature drupes from osmanthus trees, remove the outer shell, dry them slightly in the shade, and store them in moist sand. The following early spring, broadcast sow them on a pre-prepared seedbed. When the weather warms up in March, they will germinate and take root. Generally, seedlings can reach about 15 cm in height in one year, and can grow to 1 m tall in 2 to 3 years, at which point they can be removed from the nursery for planting.

4. Grafting propagation: Select one-year-old robust lateral branches from plants about 20 years old, cut two buds, graft onto privet rootstock, wrap with plastic film strips, and they can sprout in the same season. They can bloom after 4 years, but osmanthus trees propagated by this method have crooked trunks and are not suitable for use as street trees.

5. Cutting propagation: Choose February, when sap is about to flow, as the cutting season. One month before cutting, spray the cutting bed with 800-1000 times diluted trichlorfon solution to kill nematodes. 10 to 15 days before cutting, disinfect with lime water, and 3 days before cutting, rinse the cutting bed with clean water. After cutting, firm the bed soil, cover the rows with grass, water thoroughly once, and set up a shade frame. When new shoots grow to more than 6 cm, they can be moved out of the seedbed for cultivation.

Cultivation Techniques for Golden Osmanthus

1. Land preparation and fertilization: Choose acidic sandy loam with ample sunlight, deep soil layers, rich in humus, strong permeability, and convenient drainage and irrigation as the cultivation plot. In the autumn and winter of the year before transplanting, first plow the entire plot once, and dig holes according to a spacing of 1×1.5 m and planting holes of 0.4×0.4×0.4 m. Apply 2-3 kg of decomposed neutral farmyard manure and 0.5 kg of phosphate fertilizer per hole as base fertilizer. Mix the base fertilizer with the surface soil and fill it into the holes. After the fertilizer is eroded and fermented by winter snow and spring rain, it is easily absorbed by the saplings.

2. Timely transplanting: Golden osmanthus is best transplanted when the sap has not yet flowed or has just begun to flow, generally from early February to early March. When taking seedlings, retain as many roots as possible and damage as few as possible. After taking seedlings, plant them as soon as possible. If seedlings need to be transferred from elsewhere, pay attention to moisture retention to prevent dehydration. After planting, firm the soil and water thoroughly once so that the root system and soil are in close contact.

3. Water and fertilizer management: After transplanting golden osmanthus, if heavy rain causes water accumulation in the plot, dig trenches to drain it. In drought, water to combat it. In addition to sufficient base fertilizer, apply fertilizer 3 times each year: in late March, apply 0.1-0.3 kg of quick-acting nitrogen fertilizer per plant to promote height growth and more tender shoots; in July, apply 0.1-0.3 kg of quick-acting phosphorus and potassium fertilizer per plant to improve drought resistance; in October, apply 2-3 kg of organic fertilizer (such as farmyard manure) per plant to improve cold resistance and prepare for overwintering.

4. Pruning and shaping: Golden osmanthus sprouts twice each year in spring and autumn. If not pruned and bud-pinched in time, it is difficult to cultivate tall plants, and it easily forms a phenomenon of dense upper branches and sparse lower branches, strong at the top and weak at the bottom. When pruning, except for shortening branches that are growing poorly due to tree vigor or branch vigor, thinning is generally the main approach. Promptly remove sprouting branches from the base of the trunk to avoid consuming nutrients within the tree and disrupting the tree shape.

5. Loosening soil and weeding: For golden osmanthus in spring and autumn, cultivate once each in combination with fertilization to improve soil structure. Before overwintering, mound the base once and whitewash the trunk once to enhance cold resistance. Weed 2-3 times each year to prevent weeds from competing with seedlings for water, fertilizer, and light.