Osmanthus, propagated by sowing, takes about 10 years to bloom; most seedlings propagated by grafting, layering, and division will bloom in the next year; it takes 4 years for cuttings to bloom. Osmanthus that enters the flowering season should be fertilized with fertilizers based on phosphorus and potassium before August. If the season is missed, it will be difficult to promote flowering in the same year.

Generally, there are five reasons why osmanthus does not bloom

1. pH imbalance. The optimal soil pH value is 6.9 to 7.2, which means you prefer acidic soil. Since sulfur powder is a chronic soil acidification agent, you can dig 4 holes of 0.6×0.4×0.8 meters around the periphery of the sweet-scented osmanthus crown, and add 1 kg of sulfur powder. Place in holes. Or irrigate with 5% ferrous sulfate every month, and use this quick-acting agent to neutralize and improve the pH to reach normal values. It can also be improved by foliar spraying with 0.2% ferrous sulfate.

2. The fertilizer ratio is unbalanced. Osmanthus likes fertilizer, but if there is too much nitrogen fertilizer, the branches and leaves will be luxuriant and leggy, but it will not bloom; if there is less nitrogen fertilizer, the leaves will be yellow and the branches will be thin, which will affect the absorption of phosphorus and potassium fertilizers, and it will not bloom. Therefore, the sweet-scented osmanthus tree does not use chemical fertilizers as much as possible and uses farmyard manure as much as possible. The sweet-scented osmanthus tree particularly likes pig manure. There is a folk proverb that goes “To make the sweet-scented osmanthus fragrant, break the pig manure tank.” When there is no pig manure, dry cakes can be used to brew alum fertilizer water. Fertilization should be thin and frequent. Watering should be done every 10 days from February to mid-August.

3. The impact of environmental pollution. Environmental pollution damages plants to varying degrees and in different forms. For soil pollution, we must pay attention to cleaning up the sources of pollution; for air pollution, we must identify the sources of toxic chemical pollution. The sweet-scented osmanthus tree is particularly afraid of soot, so it is necessary to find ways to avoid soot damage and wash off leaf dust to eliminate its damage to the sweet-scented osmanthus tree.

4. The influence of temperature and humidity. The osmanthus tree is a long-day plant that likes strong light. Insufficient sunlight will cause the branches and leaves to grow elongated. Especially during the growth period, insufficient light will cause little or no flowering. The sweet-scented osmanthus tree likes moist soil, but avoid stagnant water, otherwise it will cause leaf fall, root rot, and no flowering. If there is a drought and water shortage, and the nutrients cannot keep up, it will also cause no flowering.

5. The impact of soil compaction. Soil is the material basis for plant growth. The water and nutrients required for plant growth and development are mainly absorbed from the soil. Its quality directly affects the quality of plant growth. The sweet-scented osmanthus tree takes root in fertile loam, which will surely make it thrive and bloom continuously.