Osmanthus Potted Cultivation Methods, Precautions, and Growth Performance

Osmanthus is one of China's traditional top ten famous flowers. There are many varieties of osmanthus, with the most common being golden osmanthus, silver osmanthus, red osmanthus, and four-season osmanthus. Four-season osmanthus can bloom fragrantly in all four seasons and is the best choice for home potted plants. Do you know how to grow osmanthus? Below, we introduce the cultivation methods and precautions for osmanthus.

Cultivation Methods for Osmanthus

1. Cuttings: The cutting time is generally in June-July or September-October, and the cutting bed should preferably be sandy loam. Select 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 roots form in 30-40 days. In winter, cold protection measures are needed, 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 throughout the year. Air layering is done in early April, while ground layering is best done in early April or during the plum rain season. When layering, either wounding or ring-barking is required, and after 1 year the layer is separated from the mother plant. For ground layering, the buried depth is about 4-5 cm, and the more bent the buried portion of the branch, the better.

3. Grafting: Grafting propagation is done in March-April. The rootstock is mostly small-leaf privet (Ligustrum sinense) or large-leaf privet (Ligustrum lucidum). The grafting method is branch grafting, and cleft grafting, cut grafting, or approach grafting can all be used. During grafting, shading is required and moisture must be maintained. For cut grafting and cleft grafting, the graft union should be as low as possible, generally cutting off the rootstock about 3 cm above the ground. After binding, mound soil up to the top of the scion so that it may root from the scion portion, 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 seeding rate of 8-10 kg per mu, covered with humus soil or burnt soil about 1.5 cm thick, and then covered with grass. Generally, germination begins 40-50 days after sowing and can last up to 50-60 days, with very uneven germination. July-September is the period of vigorous seedling growth, so pay attention to topdressing and drought resistance. One-year-old seedlings over 30 cm tall can be released from the nursery.

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

How to Grow Osmanthus So It Thrives

1. Water at the right time: For potted osmanthus, follow the principle of not watering until the soil is dry, and when watering, water thoroughly, but spray the leaves with clean water once a day. After Qingming Festival, move the osmanthus outdoors and water thoroughly once. In summer, water in the morning and evening; in winter, water around noon so that the water temperature is close to the soil temperature and does not cause sudden cold or heat. Be careful not to let water accumulate.

2. Fertilize reasonably: Osmanthus is mainly grown for its flowers, so it should be supplied with sufficient fertilizer. When new shoots emerge, apply nitrogen fertilizer 1-2 times; before flower bud differentiation and flowering, mainly apply phosphorus fertilizer. Before fertilizing, the pot soil should be slightly dry, and it is best to loosen the soil first to facilitate fertilizer absorption. The day after fertilizing, water once.

3. Repotting and soil replacement: Osmanthus should be repotted and have its soil replaced once every 2-3 years. Cut off some old roots and dead roots, place a layer of river sand or vermiculite at the bottom of the pot to improve aeration and drainage, and place decomposed cake fertilizer as base fertilizer. The soil must be pressed firm when filling. The soil ratio is not very strict; usually garden soil, composted manure, and river sand can each account for 1/3 of the mix.

4. Pruning and shaping: Osmanthus shaping generally adopts a combination of bending and pruning, preferably carried out after autumn. For plants with very poor tree form, the entire top branches can be cut off at 2/3 or 3/4 of the height. For plants with overly dense branches, thin them out. After flowering, also cut off leggy branches, dead branches, diseased and pest-infested branches, and dense weak branches.

5. Winter management: The overwintering room temperature for osmanthus should be kept at 0-5°C, with relative humidity kept at 50-80%. In winter, the cold room should have good light, especially before the buds begin to sprout in early spring, when ample sunlight is even more required. After Grain Rain the following year, arrange for the potted osmanthus to be moved outdoors. After moving out, first place them together in a wind-sheltered, sunny spot outdoors so they gradually adapt to the external environment.

6. Disease control: Common diseases of osmanthus include leaf spot, sooty mold, algal leaf spot, root rot, and iron deficiency. For leaf spot, sooty mold, and algal leaf spot, spray 0.5 Bordeaux mixture or 5% carbendazim 500-1000 times solution for control. For root rot, keep the soil loose and breathable, and do not let water accumulate.

7. Pest control: Common pests of osmanthus include sawflies, whiteflies, mites, white peach scale, and yellow slug moths. Sawflies, whiteflies, and mites can be killed by spraying 40% dimethoate 1500-3000 times solution. For white peach scale, besides manual brushing off, during the first and second instar nymph stages, spray 40% omethoate 1000 times solution or 40% fenitrothion 500 times solution for control.

Potted Osmanthus Cultivation Methods

1. Pot soil selection

Osmanthus is a very adaptable plant with low soil requirements; even clayey soil can still support its growth, though slightly acidic soil is more favorable for its growth. The pot soil can be mixed from humus soil or peat, garden soil, and sand or river sand (ratio 5:3:2). After preparation, the pH should be kept at 5.5-6.5. Before potting, disinfect the culture soil with a 0.1% potassium permanganate solution.

2. Proper watering

Osmanthus likes high temperatures and dryness, so watering must follow the principle of “two less, one more”: water less before new shoots sprout, water less on rainy days, and water more during summer and autumn droughts. At ordinary times, watering should maintain soil moisture content at about 50%, which is best. Be careful to prevent water accumulation in the pot causing root rot. In summer, the temperature should not exceed 35°C. Therefore, during hot and dry summer weather, watering must be sufficient: water once every morning, check the pot soil moisture in the evening and water again if dry, provide shade at noon to avoid the effects of high temperature, and it is best to frequently spray water around the flower pot to lower the temperature.

3. Fertilizing and topdressing tips

Osmanthus really likes pig manure. If pig manure can be obtained, apply decomposed diluted pig manure liquid once every ten days to half a month, and then in August the osmanthus will bloom very luxuriantly and be especially fragrant. If there is no pig manure, decomposed cake fertilizer liquid can also be used, preferably fertilizer containing more phosphorus and potassium, as this can promote the growth and flowering of osmanthus.

4. Proper pruning

For potted osmanthus, it is best to choose short, sturdy plants with thick trunks and evenly balanced branches and leaves. If they do not meet the requirements, they can be shortened and pruned after potting. Generally, pruning can be done twice, in spring and autumn. The first pruning is after flowering in autumn. When pruning, appropriately trim overly dense growing branches according to the plant's growth vigor, so that each side branch evenly retains sturdy short branches, and cut off leggy branches. The second pruning is before sprouting in early spring, cutting off some overwintered dead branches, weak branches, and diseased and pest-infested branches.

5. Disease and pest control

Osmanthus has many diseases and pests. The main diseases include brown spot, leaf blight, and anthracnose, while pests include red spider mites, scale insects, and others. The specific control and pesticide methods will not be explained one by one here by Uncle Gardener. Everyone should remember to observe carefully, take preventive measures, and promptly spray pesticides for control when diseases and pests are found.

[Tips] For potted osmanthus, it is best to choose varieties with strong resistance. When growing indoors, make sure the osmanthus receives sufficient light. In addition, repot the osmanthus once every 1-2 years, preferably in early spring. The new pot should be a little larger than the original one, and while changing the soil, also cut off some old roots and dead roots, so that the osmanthus can grow better the following year.

Pruning Methods for Osmanthus Bonsai

1. Pruning during the ornamental period refers to the pruning carried out after the osmanthus bonsai has taken shape, in order to maintain the beautiful form of the shaped osmanthus tree. This kind of pruning is long-term and extensive, and must be done carefully.

2. For osmanthus bonsai cultivated from tree stumps, after shaping and pruning, the trunk and main branches have already been determined. What needs further processing and pruning are the secondary branches and the finer tertiary branches. The basic points to master in processing and pruning these branches are: a branch should have a certain degree of curvature, and each branch should have differences in length, so as to appear graceful.

3. When pruning, adjust messy crossing branches, overlapping branches, parallel branches, and opposite branches, that is, cut off one of them or thin one and shorten one. The remaining branches can grow thick and strong because nutrients are concentrated. When the cultivated branch grows to a suitable thickness, carry out severe pruning to shorten it and produce the second section of branches. When the second section of branches grows to a suitable thickness, prune and shorten again. Thereafter, handle the second, fourth, and other sections of branches in the same way in sequence. Generally, leave two small branches on each section of branch, one long and one short. After many years of pruning, the branches below become short, thick, and powerfully rugged, gradually forming the desired tree shape.

In Which Month Does Osmanthus Bloom

1. Golden osmanthus: flowering period September-October, color golden yellow. Silver osmanthus: flowering period September-October, color white or yellowish white. Red osmanthus: flowering period October, color orange-red or orange-yellow. Four-season osmanthus: a small amount of flowers every month, color white. In addition, depending on the planting region, osmanthus flowering time also varies slightly. In Shanghai, Anhui, and Jiangsu, it basically blooms in October; in the Northeast region, it basically blooms in August; in Beijing, Tianjin, and Hebei, it is September; in Sichuan, Guangxi, and Shaanxi, it blooms in September.

2. Osmanthus will not bloom until it reaches flowering age. Osmanthus has a long lifespan and can generally live for decades to several hundred years, some even up to a thousand years, so its flowering age is also relatively late. Seed-grown seedlings take about ten years to bloom; cuttings take four years to bloom; grafted golden osmanthus and silver osmanthus have one-fifth bloom the following year; grafted four-season osmanthus blooms in the same year but only very few. Some large transplanted osmanthus trees can bloom in the same year, while others need one or two years to adapt before blooming.

How Much Does an Osmanthus Sapling Cost

1. Variety: The variety of osmanthus saplings determines the price level of osmanthus saplings. Osmanthus is divided into four major varieties: golden osmanthus, silver osmanthus, red osmanthus, and four-season osmanthus. Of course, each major variety also contains many minor varieties, but the prices of minor varieties under the same major variety are all about the same. Red osmanthus has the highest price and produces red flowers.

2. Size: Osmanthus saplings also come in large and small sizes, and large ones are naturally more expensive. For small saplings, the industry generally distinguishes size by sapling height (previously by tree age). At present, the most commonly planted are osmanthus saplings about one meter tall.

3. Place of origin: The place of origin of osmanthus saplings has a great relationship with price, because regional differences first lead to different costs of cultivating osmanthus saplings in different places, resulting in slight price deviations, and the transportation costs for nursery stock delivery are also greatly related to region.

4. Quantity: The purchase quantity of osmanthus saplings is also closely related to price. As everyone knows, when buying anything in wholesale quantities, the price will definitely be a bit cheaper.