Miscanthus

BUSH INVADER

Miscanthus sinensis

family: POACEAE (grass family)

Common Names:
Miscanthus, Zebra Grass, Eulalia

Also known as:
Japanese Silver Grass, Chinese Silver Grass, Chinese Grass, Chinese Sedge, Weeping Grass, Maiden Grass, Fairy Grass, Susuki

Description

Miscanthus is a tough dense upright clumping grass from Japan, China and SE Asia. It grows rapidly to 2-3m tall, tolerates most soil types except waterlogged, and survives drought once established. It thrives on disturbed areas, bushland edges, cleared areas within bushland, easements, railway lines and roadsides. It is currently promoted by the nursery industry as 'architectural' and 'water-wise'.
Below ground Miscanthus has an extensive system of shallow much-branched rhizomes. Flower stems are upright and unbranched, and somewhat flattened.
Numerous densely packed leaves, up to 10mm wide and 1-2m long, arch from the base of the Miscanthus clump. The leaf edges are rough and slightly rolled under, the tips are sharp. The mid-vein is whitish on the top of the leaf, raised on the lower side.
Large feathery fan-like flowers, silver to pink, grow on the ends of 2-3m stems rising above the foliage from the base of the clump. Main flowering time is late summer and autumn. Pollen is allergenic.
Large numbers of fluffy seeds, each with a fine twisted awn, are produced in autumn.
Cultivars and varieties of Miscanthus are numerous* - more than 50 are available in the USA, but so far only two are common here - 'Zebrinus', with white/yellow horizontal stripes on the leaves, and 'Variegatus', with longitudinal white stripes. Claims that these varieties do not produce seed should be regarded with suspicion.

Dispersal

The fluffy seeds of Miscanthus are wind blown, often aided by the turbulence of traffic; seeds can travel on tyres, shoes, clothing, and in soil. Miscanthus spreads vegetatively from its rhizomes, and will sprout from pieces of rhizome. It also spreads into bushland from garden dumping.

Impact on Bushland

Miscanthus creates dense thickets and forms extensive infestations that prevent the growth and germination of other plants. It rapidly colonises disturbed or open areas, and can invade large areas of bushland after fire, outcompeting all native species. Miscanthus is also an extreme fire risk, with a flame length of up to 8m; burning fragments make fire control difficult.

Distribution

Miscanthus is currently found mostly in the mid to upper Mountains, but has the potential to colonise all areas.

Alternative Planting

We do not advise the planting of any non-native grasses as a replacement for Miscanthus - exotic grasses almost always pose a bushland risk.

Native Plants
Red-fruited Saw-sedge (Gahnia sieberiana)
Slender Saw-sedge (Gahnia microstachya)
Lomandra (Lomandra longifolia)
Tussock Grass (Poa labillardieri)
Curly Sedge (Caustis flexuosa)
Swamp Foxtail Grass (Pennisetum alopecuroides), Poa sieberi, Caustis pentandra; for a damp area Carex apressa.

* Be on the lookout for new varieties and cultivars which may not bear the name Miscanthus at all - such as 'Maiden Grass 'Gracillimus', Dwarf Japanese Silver Grass 'Little Kitten', Purple Flame Grass 'Purpurescens', Silver Feather Grass 'Silberfeder', or Porcupine Grass 'Strictus'.

Some of the other names to look for include 'Condensatus', 'Yaku Jima', 'Morning Light', "Nippon', 'Adagio', 'Arabesque', 'Blutenwunder', 'Cabaret' 'Cosmopolitan', 'Graziella', 'Malepartus', 'Positano', 'Juli', 'Zebrinus" or 'Zebrina' (Zebra Grass), and 'Variegatus'. Gardening Australia has promoted 'Sarabande'. Distributors may claim that these plants are sterile and non-invasive, but we advise local native alternatives, such as the ones above.

Control

Whichever method is chosen, first remove flower and seed heads, wrap and send to landfill.

In the home garden Miscanthus may be dug out with a mattock. Try to remove all roots, as this plant can sprout from pieces of rhizome. If this is not practicable, scrape and paint a good section of rhizome with undiluted herbicide. Follow up with a close watch for resprouting or seedlings.

Mowing repeatedly and as short as possible throughout the growing period will eventually kill Miscanthus - usually in two seasons. However, be on the watch for seedlings.

Extensive infestations of Miscanthus are best treated by spraying. Cut the plants to the ground in late winter or early spring, before new growth starts. Remove all dead and cut matter. Spray the new growth in late spring or when there are numerous leaves 30cm or more in length. Repeat this process in autumn if necessary.

Do not burn Miscanthus. Burning increases its growth, vigour and seed production. Miscanthus germinates profusely after fire, and has the potential to spread widely.

Fuelling our Future?

Miscanthus x giganteus, a giant natural hybrid of Miscanthus sinensis, is being trialled in Europe and Asia for use as a biofuel and fibre, including paper pulp. This hybrid plant, apparently seedless, grows rapidly to 4m high. 20 tonnes of it is equivalent to 12 tonnes of coal; 30 tonnes can replace 12,000 litres of oil. It is not known to be growing in Australia.

In the Blue Mountains, Miscanthus sinensis has not yet reached these proportions - we must act now to make sure it doesn't!
photo: © Dr Marilyn Jordan, The Nature Conservancy, Long Island, New York, USA