Kapoks in full bloom

Location

AIRSIDENan Fung PlaceTKO PlazaThe MillsNF Impact Partners

February to March is a great time of year for flower gazing in Hong Kong. Tree Cotton, are commonly seen in the urban areas of Hong Kong. Tree Cotton belong to different species as Floss Silk Tree and Silk Cotton Tree. Floss Silk Tree and Silk Cotton Tree have green trunks, while Tree Cotton are grey. 

Colloquially known as the “hero trees” in Hong Kong, Tree Cotton trees get the name for their straight and sturdy bodies, and they are associated with the stories of some national heroes. Their eye-catching red flowers remain on the branches even after all the leaves have been shed. Tree Cotton has noticeable thorns. Older Tree Cotton is less spikey than the younger ones, as if they had developed a smoother character after years of experience. 

Their flowers can tell how resilient Cotton Tree is under harsh conditions. Flowers exposed to intense sunlight over time develop UV-resistant pigments, as anthocyanins work to adapt to the new environment. Some Tree Cotton trees may therefore have yellow or orange blossoms, though they are genetically identical to their counterparts with red flowers and belong to the same species. 

Flowering is a natural reproductive process of plants, so the red flowers of Tree Cotton are attractive. Tree Cotton bears fruit every April and May. Inside the large, hard seedpods are seeds. As seeds fall right under the trees, tree overgrowth or a lack of sunlight under the shade can cause deaths of young seedlings. To reproduce themselves, it is vital for trees to send their decedents away. Instead of relying on other medium to carry their seeds, Tree Cotton disperses the seeds with fibres that float in the wind. Cotton like-fibres fly in the wind, so some people may find them annoying as they may hit one’s face when they are outdoors. Many people are worried that fibres of Tree Cotton can cause respiratory diseases. Specialist (Ho, 2017) says that matters like impurities, dust and moulds in fibres of Tree Cotton can cause allergies. Many plants like Yellow Poinciana, African Tulip Tree and Yellow Pui flower at the same time as Tree Cotton releases the fibres into the air. The fibres of Tree Cotton are clearly visible while pollens of other plants are not, so people often blame the Tree Cotton for causing allergies. They would remove the unopened fruits of Tree Cotton before the fibres releasing into the air. However, as Tree Cotton can bear more fruits in a month or two, people had to remove the fruits time after time. So removal of fruits from Tree Cotton does not just disturb reproduction; it is also a waste of effort if the fibres from Tree Cotton are not the major allergens in the air. 

The fibres of Tree Cotton may annoy some people, but in fact, Tree Cotton is a great treasure: Tree Cotton is one of the major greenery species as it can alleviate the heat island effect and remove air pollutants. Their wood makes good firewood and can be made into food steamers. The flowers are ingredients of five-flower herbal tea. The fibres of Tree Cotton were once used as a substitute for cotton in medical products like pillows, as patients may be allergic to cotton; and seed oil can be extracted for making soap or lubricant. 

Tree Cotton is an important urban tree resource. They are our unsung heroes and their contributions should be celebrated. 

 Reference: Ho, Terrie[何的煒醫生].(2017). 木棉絮 真的與鼻敏感有關係嗎?  

The Conservancy Association 

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