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TREES & plants

Japanese silver grass

Specimen plant of Japanese silver grass.

Japanese silver grass, is also referred to as giant miscanthus to separate it from the smaller species of miscanthus that is commonly found in gardens.  Giant miscanthus can grow up to 14 feet tall and can be overwhelming in smaller gardens.  It is a warm season, clumping grass. Borderline hardy in zone 5.

Botanical name: 
Miscanthus floridulus
All Common Names: 
Japanese silver grass, giant miscanthus, Pacific island silver grass, sawgrass, swordgrass, tupon nette
Family (English): 
Grass
Family (Botanic): 
Poaceae
Tree or Plant Type: 
  • Grass, 
  • Perennial
Native Locale: 
  • Non-native
Landscape Uses: 
  • Specimen
Size Range: 
  • Large plant (more than 24 inches)
Light Exposure: 
  • Full sun (6 hrs direct light daily)
Hardiness Zones: 
  • Zone 5 (Chicago), 
  • Zone 6, 
  • Zone 7, 
  • Zone 8, 
  • Zone 9
Soil Preference: 
  • Moist, well-drained soil, 
  • Wet soil
Season of Interest: 
  • Early winter, 
  • Mid winter, 
  • Early summer, 
  • Mid summer, 
  • Late summer, 
  • Early fall, 
  • Mid fall, 
  • Late fall
Flower Color & Fragrance: 
  • Other
Shape or Form: 
  • Arching, 
  • Upright
More Information: 

Size and Form

This grass can grow as tall as 14 feet in one season.  It has an upright to arching habit.  It is considered a clumping grass, although it does spread slightly by rhizomes.

Plant Care

This grass tolerates a range of soil moisture from well-drained to wet.  Best in full sun.  Too much shade can lead this tall grass to become floppy.

This is a warm season grass, so its most active growth occurs in summer.  It will remain standing in winter and can act as winter interest.  It is common for the leaves of this grass to fall away in winter, leaving only the upright stems.  Since this grass remains attractive through winter, it should not be cut back until early spring, before new growth begins.  At that time, it can be cut down to the ground.

Disease, pests, and problems

Miscanthus mealybug is a possible pest.

Native geographic location and habitat

Native to Japan and Taiwan.  Commonly found in lowland areas.

Leaf description

The leaves are up to 1 1/2 inches wide and 1 to 3 feet long.  They are medium green with a very distinct white midvein.  Leaves turn beige in autumn and often fall off in winter, leaving bare stalks.

Flower description

Flowering time is late summer into early autumn (usually August to September). The tiny flowers are held in tassel-like clusters that are held above the foliage. The clusters are pinkish silver on emergence.  Flowering may not occur in colder climates.

Fruit description

The small fruit (caryopsis or grains) form along the tassel-like structures that held the flowers.  The fruiting structure takes on a silvery color for winter.

 

 

Miscanthus floridulus or Japanese silver grass