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Not just a ‘designer plant’: Miscanthus, the grass that nurtured Japanese society and culture

#miscanthus #plants #ornamentalgrasses #designerplants #gardendesign #japaneseculture #sustainableagriculture #organicgardening #satoyama

Miscanthus (in the foreground) is one of the commonest plants in the Japanese countryside

Varieties of the ornamental grass miscanthus have become a coveted ‘designer plant’ around the world in recent years. The graceful habit and fine texture of miscanthus add interest to any style of garden, be it formal, cottage, woodland, Asian, Mediterranean or xeriscape (arid). The ever-changing mood of the grass through its growth cycle—from the ‘explosion’ of fresh green shoots of early spring through to the shimmering seed-heads and rich orange-yellow tones of autumn—brings a reminder of the fleeting nature of the seasons.

Miscanthus leaves on a frosty morning in early winter

Wild Miscanthus species are distributed through parts of eastern and southern Asia, Pacific and Africa. Several species are native to Japan, of which ‘susuki’ or Miscanthus sinensis (variously known in English as maiden grass, silver grass, fairy grass, feather grass) is the most widespread. The Japanese have traditionally regarded the silvery flower panicles of susuki as a harbinger of autumn, and the grass is counted among the so-called ‘Seven Wildflowers of Autumn’ (‘Aki-no-Nana-Kusa’). Susuki is also celebrated in the poems of the 8th-century Japanese classic ‘Man’yōshū’ or ‘Collection of Ten Thousand Leaves’.

Miscanthus seed-heads shimmer in autumn light in the countryside of Niigata Prefecture, central Japan

The relationship between the Japanese and miscanthus goes back much further, however. As the main source of roofing thatch, miscanthus has been used since the prehistoric Jōmon period over 10,000 years ago. Before the advent of industrial agriculture in the mid-20th century, miscanthus was also used as a source of fertiliser, mulch and stockfeed. Miscanthus was an integral part of the traditional Japanese ‘satoyama’ system, in which natural resources were carefully managed to support environmentally sustainable agriculture and living—typically, miscanthus would be harvested for roof re-thatching, and the old thatching material would then be recycled as fertiliser for the fields. Miscanthus was such a valued commodity that communities all around Japan used to have managed plots of miscanthus grassland called ‘kayaba’—the financial district of Kayabachō in central Tōkyō derives its name from the abundance of miscanthus and reeds in the originally swampy landscape of the area.

Reconstructed middle Jōmon-period (c. 5000 years ago) dwellings at the Togari’ishi archaeological site, Nagano Prefecture, central Japan, showing thatched roof.

A thatch-roof country house in Hakuba, Nagano Prefecture, central Japan. The fundamental design of Japanese thatch roof has not greatly changed for thousands of years.

Thatch-roof houses and fields in Niigata Prefecture, central Japan—components of the miscanthus ‘recycling’ system

Kayaba plots were tended with the same care bestowed on edible crops, with particularly strict rules on the timing of harvesting so that the grasslands remained productive year after year. Fresh growth was encouraged and invasion by woody plants controlled through burning of the grassland at the end of winter, in a similar way to how the Aboriginal people in Australia managed the grasslands—perhaps not so surprising given that some anthropologists believe that the Jōmon people, the ancestral Japanese race, were descended from the same wave of people who arrived in southern Asia some 70,000 years ago, and continued their journey to the southeast to become the Australian Aboriginal people…

A patch of managed Miscanthus grassland in the Kujū volcanic range, Kyūshū, southern Japan. The grasslands are fired every spring to encourage fresh growth and maintain vegetation diversity.

Miscanthus grows densely and rapidly, making it one of the most prolific producers of organic matter in the plant world. Its hard stems and sharp-edged leaves, combined with the carbohydrate and protein-rich pith found inside the reed-like stems, result in slow breakdown of the organic matter by microbes, gradually returning the nutrients to the soil—in effect, a natural slow-release fertiliser—as well as attracting beneficial soil organisms such as earthworms. The high silica content of miscanthus leaves and stems discourages plant diseases and pests, protecting crops grown in soils enriched with miscanthus-derived humus. Miscanthus leaves and stems also make the perfect mulch as their coarse, interlocking texture prevents soil erosion, while forming a dense, moisture-retentive mat that protects the roots of crops from temperature extremes and drying out. A true all-rounder, indeed!

Dwarf miscanthus being grown in an edible garden in Melbourne (no, miscanthus is NOT edible!). The strong roots of miscanthus prevents erosion of the embankment at the edge of the mounded bed, while providing abundant organic mulch for the crops.

Close-up of miscanthus harvested for mulch, showing the hard leaves and stems, and the starchy pith inside the stems