Japanese Silver Grass (Miscanthus sinensis) is a popular, clump-forming, perennial, ornamental grass that adds interest in gardens year-round. The tall blades usually arch over to create a pretty cascading appearance.
These versatile and easy-to-grow grasses make a great garden focal point. They also work well as privacy screening, border plants, or as an alternative to hedging. The feathery plumed seed heads generally appear from late summer to early fall, but, even without the plumes, the upright stems still look good throughout the winter.
They're very popular and available in a wide variety of cultivars with differing heights and color shades. They're most commonly found in silver tones, but pink, purple and red shades are also available. Some of the dwarf cultivars don't even reach up to one meter in height, but most are taller, with some growing to be over ten feet tall.
Most of the cultivars are sterile, but the main species is considered invasive in many parts of the United States.
Care should be taken to select an appropriate variety in terms of size and potential to spread.
|Botanical Name||Miscanthus sinensis|
|Common Name||Japanese Silver Grass, Giant Miscanthus|
|Plant Type||Herbaceous perennial|
|Mature Size||32 inches (dwarf varieties) up to 8 feet|
|Sun Exposure||Full Sun/Partial Shade|
|Soil Type||Tolerates a variety|
|Soil pH||Tolerates a variety|
|Bloom Time||Late summer/early fall|
|Flower Color||Commonly purplish or reddish silver|
|Hardiness Zones||5 to 9|
|Native Area||Japan, China, Korea and Taiwan|
How to Grow Japanese Silver Grass
Japanese Silver Grass does best in full sun and a fertile and moist soil. They're a relatively hardy species and will produce good results with minimal effort.
These grasses prefer a full sun position. They can still do well in partial shade, but they may not be as vigorous. If they're in a shady spot, the grass tends to be overly floppy. The color intensity and amount of blooming will also be impacted.
Japanese Silver Grass can grow in a variety of different soil types. Their preference, though, is for a fertile, moist and loamy option. Whatever type the soil is, it needs to be well-drained.
This species does best in a soil that is kept consistently moist, but not waterlogged. Once the surface of the soil becomes dry, this is generally a good indicator that more water is required.
Although it prefers moisture, once the plant is fully established, it can handle periods of drought and still survive. Be careful about how you water your Japanese Silvergrass. Overhead pouring can impact on how effectively the water will reach the roots, and overly wet blades can increase the chance of fungi developing.
Temperature and Humidity
These plants, when dormant, are hardy down to around minus five degrees Fahrenheit. They aren't suited to regions that are susceptible to late spring frosts as this can damage new growth. The plants might not flower in colder regions either.
Japanese Silver Grasses are suited to gardens that are exposed to strong winds - they handle these conditions well.
If you're growing your Japanese Silver Grass in their preferred rich and fertile soil type, they won't need any feeding during their first year of growth.
If you want to boost growth and bloom potential after it has established, using an organic fertilizer during the summer months is recommended.
Propagating Japanese Silver Grass
Root division works well if you plan to propagate new plants from your Japanese Silver Grass.
Division is best done in late spring after any frost has passed. Large divisions usually take well being planted straight out into their permanent position. They just need moist and fertile soil and plenty of sun. Make sure you have a decent amount of roots and foliage, several shoots are needed to ensure success.
If the division is smaller, it may produce better results if it's first potted up and grown with some shade in a cold frame. Once established, it can then be planted out sometime during late spring or summer. If you have a large and mature plant, you may need to use a saw to divide the sections.
Because Japanese Silver Grass also grow rhizomes, you can propagate from a healthy root strand too. It'll just take a little longer to see results than it will from simple division.
Varieties of Japanese Silver Grass
There are over 150 Japanese Silver Grass Cultivars. They can vary greatly in their height, colors and patterns. Some of the more popular varieties include:
- 'Gracillimus' - This grows easily, with purple flower plumes providing winter interest. Good for a larger space or as a screen as it can reach heights of up to six feet.
- 'Silberfeder' - A tall cultivar suited to cooler climates, hardy to USDA zone 4. The 8' tall plant produces pinkish-silver plumes.
- 'Zebrinus' (Zebra Grass) - adds a splash of unique interest in your garden because of its variegated foliage and pinkish summer plumes. Grows 5' to 7' tall.
- 'Strictus' - this variegated variety is particularly suited to be growing at the edge of garden ponds. It's more tolerant of wet soil conditions than most other cultivars. Variegated like 'Zebrinus' but more upright and compact, with pink plumes.
The grass is still a nice feature even when dormant in the winter, so it's best to wait until early spring before you cut it back. Doing this, before new growth begins, can help to encourage vigorous growth and strong blooms.
Growing From Seeds
Germination of Japanese Silver Grass is pretty fast. If they're sown on the surface of a moist, fertile mix, it'll usually occur within two weeks. Keeping them covered, ideally in a greenhouse or similar, for their first winter is recommended.
They can then be transplanted to their permanent position in late spring or summer. Be aware that Japanese Silver Grass takes a full year before any flowering will be seen.
When you plant them out, make sure you allow enough space as these wide-clump-forming species can take up a decent amount of ground. The space needed will vary depending on the mature size of the cultivar you have selected.
Most of the cultivars are sterile, but the main species of Japanese Silver Grass is considered invasive in many parts of the United States.