Latest Cultivation Techniques and Methods Tutorial for Osmanthus Bonsai
Osmanthus is evergreen year-round, with luxuriant branches and leaves, blooming in autumn with a rich fragrance. It is widely used in gardens, often as a landscape tree, planted singly, in pairs, or in clusters and groves. In classical Chinese gardens, it is often combined with buildings, rocks, and stones, with multi-stemmed shrub-type plants placed near pavilions, terraces, towers, and chambers. Now let us take a look at osmanthus bonsai cultivation techniques!
Osmanthus Bonsai Propagation Methods
1. Sowing: Osmanthus fruit usually ripens from April to May. When the fruit skin turns from green to purplish black, it can be harvested. Osmanthus seeds have after-ripening, requiring at least half a year of sand storage. After harvesting, sprinkle with water and pile to ferment, remove the flesh, place in a cool place to let the seeds dry naturally, and store mixed with sand. After sand storage, they can be sown in autumn or spring. Before sowing, prepare the soil well and apply sufficient base fertilizer; they can also be sown in indoor seedbeds. When sowing, place the seed hilum sideways to prevent the radicle and young stem from bending, which would affect seedling growth in the future.
2. Grafting: Osmanthus grafting rootstock mostly uses privet (Ligustrum), small-leaf privet, Chinese privet, water privet, etc. When propagating seedlings in large quantities, small-leaf privet is mostly used. Before spring sprouting, cut the rootstock at 5 cm above the ground. Cut 1-2 year old robust osmanthus branches 10-12 cm long, shave one side of the base into a 2-3 cm cut surface, and shave the opposite side into a 45-degree small bevel. Make a vertical cut about 1/3 deep on one side of the rootstock, about 2-3 cm deep. Insert the scion into the cut, align the cambium, tie tightly with a plastic bag, then bury in soil for cultivation.
3. Cuttings: Usually before spring sprouting, use one-year-old fully developed branches, cut into 5-10 cm lengths, remove the lower leaves, keep 2-3 green leaves on top, and insert into river sand or loess seedbeds. Plant spacing is 3*20 cm. After inserting, water or spray promptly, and shade. Maintain a temperature of 20-25°C and relative humidity of 85-90%. After 2 months, they can root and be transplanted.
4. Layering: Osmanthus can be divided into low layering and high layering. The low layering method is to select 1-2 year old branches from the lower part of a relatively robust low-trunk mother tree in spring to early summer, select easily bendable parts, cut or ring-bark with a sharp knife, press into a 3-5 cm deep trench, and fix the pressed branch with wooden sticks. The high layering method is to select 1-2 year old robust branches from the mother tree in spring, cut a ring or ring-bark as in the low layering method, then apply culture medium to the wound, tie tightly with plastic bags above and below. After rooting in autumn, cut away from the mother plant for maintenance.
Osmanthus Bonsai Cultivation Techniques
1. Pot selection: Osmanthus has green leaves and yellow flowers, evergreen in all seasons. It is suitable to choose a deeper round pot or square pot. The pot mouth diameter should roughly match the spread of osmanthus branches and leaves, which benefits root development and growth. The pot texture is best with purple clay pottery pots or glazed pottery pots. The color is better with purple or ochre, which can form a sharp contrast with the flower and leaf colors, increasing its ornamental effect.
2. Soil: Osmanthus likes fertilizer. It is suitable to use fertile, loose, well-drained sandy loam. The culture soil for potted osmanthus is usually made by mixing 1/3 garden soil, 1/3 composted manure, and 1/3 river sand. Pay attention to disinfection treatment so as not to infect pests and diseases.
3. Planting: Osmanthus is suitable for planting in early spring or autumn. Before potting, lay a layer of river sand or vermiculite at the bottom of the pot to facilitate ventilation and drainage, then spread a layer of peat soil or fine mud about 2-3 cm thick on top, up to 1/3 of the pot depth. Then, put the osmanthus seedling with a root ball into the pot, fill with culture soil, press tightly with fingers, fill soil until close to the pot mouth. The soil surface should be 2-3 cm lower than the pot mouth to facilitate watering and fertilizing. After planting, water thoroughly, then move to a shaded place for about 10 days to let it “adapt to the pot” and gradually resume growth.
4. Processing: Osmanthus has strong sprouting ability and tolerates pruning. One or two years after potting, process and shape during the plum rain season or after autumn flowering, using a combination of wiring and pruning. The trunk can be wired into a curved trunk form or slanting trunk style. If the trunk is relatively tall, it can be appropriately shortened to make new branches sprout from the base, so the lower part will not be empty, or heavily prune the upper branches and overly dense branches to stimulate new branches from the lower trunk, maintaining upper-lower balance, making the tree shape beautiful and flowers and leaves luxuriant.
5. Tree shape: Osmanthus styling is best made into curved trunk style, slanting trunk style, or flowing style. The tree posture spreads slantingly, with dense branches and leaves, simple and natural, most resistant to appreciation. When flowering, the rich fragrance overflows and refreshes the heart.
Osmanthus Bonsai Maintenance Management
1. Placement: Osmanthus tree bonsai is suitable to be placed in a warm, sunny place. In summer, it needs appropriate shading to avoid direct strong light. In areas north of the Yangtze River, it must be put indoors for winter, and a room temperature of 0-5°C is relatively safe. It can be taken out around the Awakening of Insects (Jingzhe) in the following spring.
2. Watering: For osmanthus tree pot soil, master the principle of not watering when dry, and watering thoroughly when watering. Generally, water once every 3-4 days in spring and autumn, once a day in high summer temperatures, and once every 7-10 days in winter. In summer, water in the morning and evening; in winter, water around noon, so that the water temperature is close to the soil temperature, not causing sudden cold or heat that damages the root system. In autumn, water appropriately. In the plum rain season, prevent the pot soil from being too wet or waterlogged.
3. Fertilizing: Osmanthus tree bonsai is mainly for flower viewing, so it should be supplied with sufficient fertilizer. When shoots sprout, apply nitrogen fertilizer 1-2 times to promote branch and leaf growth. Before flower bud differentiation and flowering, mainly apply phosphorus fertilizer. Before fertilizing, the pot soil should be slightly dry, and it is advisable to loosen the soil first for fertilizer absorption. The day after fertilizing, water once. If using compost or manure, it must be completely decomposed before use. When applying chemical fertilizer superphosphate, its concentration cannot exceed 2%.
4. Pruning: The shaping and pruning of osmanthus trees is suitable after autumn, cutting off overly strong upper branches to balance tree vigor. Overly dense branches should be thinned, and diseased and weak branches removed, so nutrients are concentrated, benefiting flowering. Shaping and pruning combined with water and fertilizer management can improve the healthy growth of osmanthus bonsai and maintain a beautiful posture.
5. Repotting: Osmanthus bonsai can be repotted and soil changed every 2-3 years. The new pot should be a bit larger to benefit osmanthus root growth. Combined with repotting, cut off part of the old roots and dead roots, remove part of the old soil with a bamboo stick, replace with loose and fertile new culture soil, and place decomposed cake fertilizer as base fertilizer at the bottom of the pot. When filling soil, it must be compacted, which can promote osmanthus flowering and luxuriant leaves.
6. Diseases: Common osmanthus diseases include leaf spot, sooty mold, algal leaf spot, root rot, iron deficiency, etc., which should be prevented and controlled according to the disease situation. Leaf spot, sooty mold, and algal leaf spot can be controlled by spraying 0.5 Bordeaux mixture or 5% carbendazim 500-1000 times solution. For root rot, attention should be paid to keeping the soil loose and breathable, not waterlogged. If root rot is caused by fungi, it can be irrigated at the root with 200-300 times solution of amobam.
7. Pests: Common osmanthus pests include sawflies, whiteflies, mites, long white scale insects, yellow stinging moths, etc. Sawflies, whiteflies, and mites can be sprayed and killed with 100% dimethoate 1500-3000 times solution. For long white scale insects, besides manual brushing, during the first and second generation nymph stages, they can be sprayed and killed with 400% omethoate 1000 times solution or 40% fenitrothion 500 times solution.