Beyond a Wild Grass - Silvergrass

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Under the sunshine, the glowing plumes of Silvergrass sweeping across large expanses of hillsides in autumn and winter form magnificent scenes, which feature in many landscape photographs or selfies. Unknown to many, though, Silvergrass has been widely used in people’s daily lives since ancient times. The valuable grass is even considered to be a future biofuel, to help beat environmental problems brought about by fossil fuels.

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Silvergrass is a member of the large Family of Poaceae, most members of which are what we usually call wild grasses. There are two species of the genus Miscanthus, to which Silvergrass belongs, in Hong Kong: Chinese Silvergrass (Miscanthus sinensis) and Many-flowered Silvergrass (Miscanthus floridulus). The former is 1-2 metres in height and grows on slopes, while the latter can grow up to 2-4 metres and is more commonly found in wetlands at the foot of hills. The two species appear very similar.

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Taking photographs of Silvergrass has become a hot trend in recent years. On social media, we often see photographs shared with the “Silvergrass” label. The fact is, many people have mixed up Silvergrass and other grasses. It is indeed a rather difficult and specialised task to identify the different grass species. Grasses are distinguished by the small inflorescences and ways the sheath is differentiated from the leaf stalk. Sometimes it requires the use of a microscope to observe the features of different species.

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In the Hong Kong countryside, there are a few grasses which look alike and are easily mistaken for Silvergrass. They include: Lalang Grass (Imperata cylindrical), Plume Grass (Pennisetum alopecuroides) and Common Reedgrass (Phragmites australis). Compared to Silvergrass, Lalang Grass has a whiter inflorescence and shorter shoot, and Plume Grass has no branches in the inflorescence. Common Reedgrass is aquatic and grows in wetlands or the coast. No matter whether you can identify them correctly, it’s most important that you appreciate and treasure them!

Daily objects

The fast growing and sturdy properties of Silvergrass make it a good choice for making daily articles. In the past, Silvergrass sheath was used to make shoes. Silvergrass is also livestock fodder and material for building houses and making paper. Today, it is still used in woven baskets and lamp covers. Dried inflorescences are used directly to make brooms. Silvergrass also has medicinal value. Its roots and stems are antitussive, diuretic, and can detoxify the blood.

Silvergrass is much valued in Japanese culture too. Its inflorescence carries the hope for strong growth of rice crops, for instance. In the past, every village would set up a special ground for storing Silvergrass for daily use.

New biofuel

In recent years, scientists in Europe and mainland China have been investigating the potential of Silvergrass as biofuel for renewable energy. The conventional biofuels make use of starchy crops (such as corns), which inevitably affects the supply of staple food. Silvergrass, on the other hand, is a grass and non-food crop. Its characteristics of speedy growth, easy to dry, perennial growing and resistance to pests and diseases make it a viable candidate for the development of biofuel.

European scientists even cross-breed Chinese Silvergrass (Miscanthus sinensis) and Amur Silvergrass (Miscanthus sacchariflorus) – a species native to subtropical Asia — to produce Giant Miscanthus (Miscanthus × giganteus), which grows even faster and taller. The species is being cultivated at large scale to supply power plants in some regions such as England and Wales. The plans for the future are to make Silvergrass a foundation material for making alcohol, biodiesels, synthetic plastics and paper pulp fibres, etc.