Why doesn't the osmanthus tree bloom?

Osmanthus trees are shade-tolerant and bright green in color, suitable for growing in less sunny conditions. The planting process of osmanthus trees is relatively long, but there may be a problem of not blooming. So why don't osmanthus trees bloom? Let's learn why osmanthus trees don't bloom.

Why doesn't the osmanthus tree bloom?

There are several reasons why the osmanthus tree does not bloom :

Smoke pollution In recent years, some reports have suggested that sweet-scented osmanthus leaves are highly resistant to pollutants such as sulfur dioxide, hydrogen fluoride, and chlorine, so many urban parks have planted sweet-scented osmanthus trees. But in fact, because sweet-scented osmanthus trees are native to mountainous areas with poor environmental conditions, their growth conditions require clean air. In the air containing smoke, although it may not necessarily cause scars on the leaves, it is enough to inhibit its normal flowering. Sweet-scented osmanthus trees are a species that is not resistant to smoke pollution and should not be planted in places with dense factories.

In addition, on roadsides with heavy traffic, the severe traffic dust often affects the flowering of osmanthus trees.

Soil conditions are not suitable for the growth of sweet-scented osmanthus trees. Sweet-scented osmanthus trees are native to the acidic soil areas in southern China. The soils in major production areas such as Suzhou, Hangzhou, and Guilin are acidic or slightly acidic, with a pH value of about 5.6-6.8. However, the soils of some gardens in cities have become alkaline due to the long-term influence of industrial dust, construction waste, and excessive application of human feces and urine. Therefore, in areas with alkaline soil and high salt content (such as coastal areas), sweet-scented osmanthus trees do not grow well, and even fewer can bloom.

Sweet osmanthus trees are native to mountainous areas and require soft soil with good drainage. However, many cities have flat terrain and poor drainage. Some cities have high groundwater levels (for example, the groundwater level in Shanghai is only about 0.5 meters), which causes the root system of sweet osmanthus trees to develop poorly. Good drainage is an important condition for the growth of sweet osmanthus trees.

Improper maintenance and management: the roots and the soil they carry are not well protected during transplantation , or the above-ground branches and leaves are not properly pruned, resulting in physiological imbalance between the underground roots and above-ground branches and leaves, and improper maintenance and management after planting.

Osmanthus fragrans is a slow-growing, positive tree species. When planted with other tree species, it is easily shaded by neighboring fast-growing trees. According to surveys, the top of the osmanthus tree crown, especially when it is shaded by other tree species facing south, can hardly bloom normally. It can only grow vigorously in places with sufficient light. However, osmanthus fragrans cannot tolerate long-term exposure to the sun and drought. We have seen more than once that in the hot summer, especially in gardens with more cement paving, osmanthus fragrans often have abnormal large leaf drop, causing the tree to decline and fail to bloom. In tropical areas, such as Hainan Island, Taiwan and Lingnan, although there are osmanthus fragrans trees, their growth and production are far inferior to those in subtropical areas, indicating that the osmanthus fragrans flowers have strict requirements for climatic conditions.

Since some pests with chewing mouthparts, such as thorny ammonium and bag moth, do not like to eat osmanthus tree leaves and are relatively easy to control, some people mistakenly believe that there is no need to pay special attention to the diseases and pests of osmanthus trees. In fact, this is not the case. It is true that the phenomenon of osmanthus trees dying due to diseases and pests is indeed extremely rare, but there are several diseases and pests that can endanger the flowering of osmanthus trees. Small and inconspicuous pests such as red spider mites, whiteflies, scale insects and armyworms often make osmanthus tree leaves wither and grow weak, especially in poorly ventilated, shaded and humid places. In addition, in places with local waterlogging, the roots of osmanthus trees are easily harmed by some facultative parasites such as Fusarium, causing root rot. These diseases and pests can inhibit the flowering of osmanthus trees, but they are often ignored by people.