Is Osmanthus suitable for growing on a balcony? A detailed guide to care essentials

Osmanthus is the collective common name for many trees in the Chinese genus Osmanthus, also known as rock osmanthus, wood osmanthus, golden millet, and so on. It is an excellent garden tree that combines greening, beautification and fragrance, being both ornamental and practical, pure enough to banish dust and rich enough to carry far, truly outstanding, and it also has a great many horticultural varieties, the most representative being golden osmanthus, silver osmanthus, reddish osmanthus, sweet osmanthus, and so on. Now let us take a look together at whether osmanthus is suitable for growing on a balcony!

Can osmanthus be grown on a balcony?

Osmanthus is suitable for growing on a balcony. Osmanthus is quite suitable for growing at home. Although many city residents now live in apartment buildings, as long as a suitable microclimate can be created for the normal growth and development of osmanthus, it can likewise bloom in residents' homes. Osmanthus loves sunlight; although it tolerates partial shade, it grows well and produces many flowers with a rich fragrance under conditions of ample light, so potted osmanthus for the home should be placed in a sunny spot on the balcony for care. However, osmanthus is averse to soot and ash; if the air pollution around a home balcony is severe, then osmanthus cannot be cultivated.

Why does an osmanthus tree fail to bloom?

1. Improper selection of seedlings: Some varieties of osmanthus tree (such as purple osmanthus) only bloom after they have grown into trees, and if purple osmanthus is mistakenly propagated by cuttings or grown into seedling stock, it is very difficult for it to bloom. Osmanthus seedlings should be grafted seedlings using mature branches of good varieties as scions, or seedlings obtained by air layering from flowering branches or even the base, which are not only of good quality but also likely to bloom after surviving.

2. Improper cultivation: The osmanthus tree likes sandy soil best, and in soil with relatively high alkalinity it often blooms very little. If the roots are damaged or frozen during transplanting, the growth vigor will inevitably be weakened, and it will not bloom for 3 to 5 years. The osmanthus tree loves light and fears warmth; long-term insufficient light may prevent blooming. Soil that is too wet causing root rot, or prolonged high temperature and dryness, can also affect flower bud differentiation.

3. Nutrient imbalance: The osmanthus tree is a fertilizer-loving plant, but fertilizer is not a case of the more the better. Every plant has a proportion of fertilizer components such as nitrogen, phosphorus and potassium that needs to be balanced internally. With too much nitrogen fertilizer, the branches and leaves flourish and the shoots grow excessively, and it simply will not bloom. With too little, the leaves yellow and the branches become thin, which affects the absorption of phosphorus and potassium fertilizers, and it also will not bloom.

4. Caused by disease: The osmanthus tree fears chlorine gas and does not tolerate oil smoke. With heavy oil smoke it grows poorly, the leaves become smaller and fall off, and it cannot bloom. The osmanthus tree is also susceptible to pests and diseases such as anthracnose and scale insects, and if not treated in time, these likewise affect blooming. In addition, mistakenly pruning the spring shoots will affect blooming that year. Too many blooming osmanthus branches will weaken the growth vigor and affect blooming in later years.

How to grow a potted osmanthus tree?

1. Water at the right time: For potted osmanthus, the principle is not to water when the soil is dry, but to water thoroughly when watering, while spraying the leaves with clean water once a day. After Qingming Festival, move the osmanthus outdoors and water it thoroughly once. In summer, water in the morning and evening, while in winter water around noon, so that the water temperature is close to the soil temperature and there is no sudden cold or heat; be careful not to let water accumulate.

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

3. Repot and change the soil: Every 2 to 3 years, osmanthus should be repotted and the soil changed once, cutting away part of the old roots and dead roots. Put a layer of river sand or vermiculite at the bottom of the pot to facilitate aeration and drainage, and place decomposed cake fertilizer as base fertilizer; when filling with soil, it must be pressed firm. The soil ratio is not very strict; usually garden soil, composted barnyard manure and river sand can each make up 1/3 of the mix.

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

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

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

7. Pest control: Common pests of osmanthus include sawflies, whiteflies, mites, long white scale insects, yellow stinging moths, and so on. Sawflies, whiteflies and mites can be killed by spraying 40% dimethoate 1500 to 3000 times dilution. For long white scale insects, besides manual brushing off, the first and second generations of nymphs can be killed by spraying 40% omethoate 1000 times dilution or 40% fenitrothion 500 times dilution.