How to Grow Rixiang Gui (Osmanthus fragrans 'Rixiang Gui')? A Detailed Guide to the Latest Cultivation Methods
Rixiang Gui is a horticultural cultivar of Osmanthus fragrans (sweet osmanthus), also known as Muxi, Jiulixiang, Jinsu, and so on. It gets its name from its characteristics of continuous blooming and intense fragrance, combining greening, fragrance, and color functions in one. It can be cultivated into a beautifully shaped spherical small tree, or into a dense spherical large shrub, and can also be grown in pots or used for cut flowers. Now let us take a look together at the cultivation methods for Rixiang Gui!
Growth Habits of Rixiang Gui
Rixiang Gui has wide adaptability and strong stress resistance. It prefers neutral to slightly acidic soil rich in organic matter, requires a cool and humid microclimate, and has a certain degree of cold tolerance. Its budding period each year comes relatively early. In Northeast and North China, potted plants can bloom normally; south of the Qinling Mountains and the Huai River, it can overwinter safely in the open ground; and in provinces and regions with high temperatures year-round, such as Fujian, Guangdong, Guangxi, and Hainan, it also adapts fairly well and can bloom on schedule each year. Its flower buds can continuously differentiate, and it has the remarkable characteristic that even tender spring shoots and young branches can bloom, while lignified old branches can also bear densely clustered flower buds and bloom. This ensures the long duration and continuity of Rixiang Gui's flowering. A small seedling with two leaves in its current year can already bloom, something ordinary sweet osmanthus cannot compare with.
Propagation Methods of Rixiang Gui
1. Layer by bending branches: Usually in late March to early April, around the mother plant, depending on how many branches can be layered, dig a small trench 20 cm deep and 20 cm wide along the direction in which the branches naturally extend, then bend the branches into the trench, fill the trench completely with fertile soil and firm it down, water thoroughly, and then mound the soil at the layered part into a steamed-bun shape.
2. Air layering: Usually between September and October, split one section of a moso bamboo tube into 2 pieces, fill it with moist soil, and fit it around a vigorous branch of Rixiang Gui. Support it with a frame, add water frequently, and keep the inside of the tube moist. After more than 1 month, new roots will grow. The following spring, remove it and transplant it, and it becomes a sweet osmanthus tree, which can bloom in about 3 years.
3. Seed propagation: Each year in late May to early June, pick ripe drupes from the Rixiang Gui tree, remove the outer shell, dry them slightly in the shade, and store them in moist sand. In early spring of the following year, sow them on a pre-prepared seedling bed. When the weather warms in March, they will germinate and take root. Generally, seedlings can reach about 15 cm in height in one year, and in 2 to 3 years can grow to 1 m tall, at which point they can be lifted from the nursery and planted out.
4. Grafting propagation: Select one-year-old vigorous side branches from a plant about 20 years old, cut sections with two buds, graft them onto a privet (Ligustrum) rootstock, wrap them with strips cut from plastic film, and they can sprout in the same season. They can bloom after 4 years, but sweet osmanthus trees propagated by this method have crooked trunks and are not suitable for use as street greening trees.
5. Cutting propagation: Choose February, when the sap is about to start flowing, as the cutting season. One month before cutting, spray the cutting bed with trichlorfon at 800 to 1000 times dilution to eliminate nematodes. 10 to 15 days before cutting, disinfect again with limewater, and 3 days before cutting, rinse the cutting bed with clean water. After inserting the cuttings, firm the bed soil, cover the rows with grass, water thoroughly once, and set up a shade frame. When the new shoots have grown to more than 6 cm, they can be moved out of the seedling bed for cultivation.
Cultivation Methods for Rixiang Gui
1. Soil selection: Rixiang Gui is best grown in loose sandy loam containing organic matter. Mushroom residue, sawdust, peat, mountain forest leaf mold, and similar materials can also be used (the substrate should be chosen so that the potted plant's root system can grow and breathe). The substrate's pH should be neutral and slightly acidic. After choosing the substrate, it is best to also disinfect and sterilize it (for example, using thiophanate-methyl, dijunqing, carbofuran, and other agents).
2. Reasonable watering: Newly planted Rixiang Gui should be watered once thoroughly. Its water requirements are similar to those of other flowering plants; soil that is too dry or too wet will both affect growth and development. If young tender branches and leaves are found wilting, place the flowerpot in a basin of clean water deep enough to submerge one quarter of the pot soil, and after about 1 hour it will recover to normal. Excess water can also cause oxygen deprivation and root rot. But avoid watering with alkaline water such as tea water or laundry detergent water.
3. Timely fertilization: Because Rixiang Gui consumes relatively more nutrients due to its continuous blooming, more phosphorus fertilizer should be applied to promote its sustained flowering. Based on this, its fertilization standard should follow the principle of “light fertilizer applied frequently.” Normally, an appropriate amount of organic fertilizer can also be added, but be sure not to fertilize excessively or too frequently. Fertilization should be combined with watering, generally once per flowering period.
4. Shaping and pruning: For Rixiang Gui, according to the desired tree form, cut away some water sprouts, overly dense branches, dead branches, diseased branches, and so on. For newly planted potted plants, part of the tender branches should be pruned. Pruning is generally carried out after the tender shoots emerge but before they have lignified.
5. Pest and disease control: Common diseases of Rixiang Gui include leaf blight and anthracnose, which can be controlled with 800 times dilution of “Duojunqing” or “Tobuzin.” Common pests include red spider mites and scale insects, which can be controlled with 1000 times dilution of “chlorobenzilate” and “Supujie” respectively.
Daily Care of Rixiang Gui
1. Light management: Rixiang Gui prefers light. In a sunny place, its leaves are emerald green, its branches and trunk are thick and strong, and its flowers are abundant and fragrant. If placed in a shaded spot with insufficient sunlight, its branches and leaves will be sparse and the fragrance of the flowers will be faint. Rixiang Gui grows most vigorously when the temperature is between 15°C and 30°C, but in summer it is susceptible to high temperatures and scorching sun burning tender leaves and young buds, so potted seedlings in midsummer should be placed in a well-ventilated, cool place.
2. Temperature control: The lowest extreme temperature in the place of origin of Rixiang Gui is -7°C, and the highest extreme temperature is 38°C. The normal flowering temperature is 2°C to 22°C. If the summer temperature is too high, you can lower the temperature and increase humidity by spraying water on the leaves. If the winter temperature is too low, insulation should be provided.
3. Humidity control: Rixiang Gui likes warmth and moisture. Normal humidity can be controlled at 70% to 85%. Loss of water in the pot soil will cause the leaf edges to scorch and dry. In summer and autumn, when temperatures are high and the air is dry, water more to keep the pot soil moist, and also frequently spray water on the plant and the pot surface. In winter and spring, watering should be appropriately reduced. During the plant's growth process, water must not accumulate in the pot, otherwise it can very easily cause root rot.
4. Repotting and soil replacement: Rixiang Gui has strong vitality and should be repotted and given fresh soil every year to avoid large numbers of fibrous roots touching the pot and affecting water and fertilizer uptake. The best times for repotting are February to March in spring and September to October in autumn each year. When repotting and replacing the soil, retain part of the original soil (roots), remove the rest of the root soil, and fill new nutrient soil around the edges of the pot. Water thoroughly, care for it in a shaded place for about 20 to 30 days, then move it to a ventilated, sunny place for management.
5. Promoting flowering: The optimal temperature for flower bud differentiation in Rixiang Gui is 6°C to 8°C, the temperature for the greatest flowering quantity is 16°C to 18°C, and the air humidity is 75% to 85%. At the same time, a certain amount of short-day light is required. Therefore, we can promote its flowering by improving the micro-environment (such as removing buds to control vegetative growth, shading to control light, spraying water on leaves to lower temperature and increase air humidity, and so on).