Ornamental grasses are a valuable part of any garden, providing texture and movement over a long season. Japanese blood grass adds an element of vibrant color to the border, giving you a red accent for your garden design that isn't limited to a particular blooming period. Although Japanese blood grass has developed a thuggish reputation in some gardening circles for its invasive qualities, you can choose a sterile cultivar or use container culture to control this exuberant plant.
|Botanical Name||Imperata cylindrica|
|Common Name||Japanese blood grass; cogongrass|
|Mature Size||1 - 2 ft.|
|Soil Type||Moist but well-drained|
|Soil pH||Acidic, alkaline (6.5-7.5)|
|Hardiness Zones||5, 6, 7, 8, 9|
Japanese Blood Grass Care
Japanese blood grass is an easy-to-grow ornamental grass that provides reliable color as the season progresses. The serrated foliage is unattractive to deer and rabbits, and the rapid growth habit fills in hillsides quickly to help with erosion control. This vigorous plant needs little care to thrive. However, keep an eye on blood grass, as it can quickly get out of hand.
Some states have declared the Japanese blood grass a noxious weed. The species is especially virulent in the landscape. While the red form is technically not invasive, it can easily revert to the green form of the plant, which has been named one of the 10 most invasive weeds in the world.
Japanese blood grass shows its best coloration in full sun, at least six hours of direct sun per day. In Southern gardens, some afternoon shade is tolerated.
Provide your Japanese blood grass with moist, well-drained soil. The plants grow well in sandy soils, and can even thrive in coastal gardens.
Japanese blood grass grows vigorously in the presence of moist soils, but it tolerates drought conditions as well. Only irrigate the plant as necessary to prevent the browning of foliage.
Temperature and Humidity
Japanese blood grass grows well in a wide range of temperatures. In the warmer reaches of its zone boundaries, the plants can spread and displace other garden plants with their rhizomes. Both humid and dry conditions are tolerated by the grasses.
No fertilizer is needed to grow Japanese blood grass successfully, as the plants will grow in poor soil. Extra nutrients may cause the grass to grow aggressively.
Types of Japanese Blood Grass
Because of its invasive tendencies, gardeners should take care to purchase only the named, sterile cultivars, which include 'Red Baron' and 'Rubra.' These grasses don't look different from the species, but have the important attribute of forming few or no flowers, and spreading slowly by rhizomes rather than quickly taking over the flowerbed.
Japanese blood grass plants look attractive throughout the winter months and may be somewhat evergreen in most climates. Leave the plants standing until spring, and then cut them back, or just trim away dead foliage.
Propagating Japanese Blood Grass
Japanese blood grass is easy to propagate by division, even for beginners. Cut into the plant with a spade in the spring or fall, when growth is most active. Don't be afraid to make many small divisions as needed, as the plants will grow and mature rapidly.
Growing Japanese Blood Grass From Seeds
The desirable named cultivars of Japanese blood grass do not produce viable seeds. It isn't recommended to grow seeds of the invasive species type.
Potting and Repotting
Japanese blood grass isn't picky about potting soil or container types. Grasp the plant by the root ball and loosely pack the potting medium around the plant. Repot in the spring or fall as needed when plants become crowded with spreading rhizomes.
No special care is needed for overwintering this plant. The colors stay vibrant through cooler temperatures, so many leave it alone and cut it back in early spring.
Common Problems with Japanese Blood Grass
Japanese blood grass isn't bothered by any pest or disease problems. Plants that revert to green should be removed to avoid significant invasive habits.
Can Japanese blood grass grow indoors?
What is an alternative to Japanese blood grass?
Purple fountain grass (Pennisetum setacecum) gives instant cachet to summer borders and container gardens. The dark purple stems and bronzy plumes make handsome companions for green, pink, and purple plants. Purple fountain grass is a tender perennial that is often treated as an annual.