Garden Scheme
Plant library · Ornamental Grasses
Imperata cylindrica 'Rubra'
Japanese Blood Grass is a compact perennial ornamental grass with upright blades whose blood-red tips strengthen toward fall. At about 18 inches tall and wide, it reads as a small, vertical foliage accent rather than a screen or large backdrop plant. It seldom flowers in most gardens, so the foliage is the only reason to reserve it a visible place in the plan.
Space Japanese Blood Grass 18 inches apart, measured center to center (45 cm).
The mature spread is about 18 inches (45 cm), so neighboring plants just meet at maturity without crowding.
Treat 18 inches as a planning baseline — cultivar and local growing conditions shift the final footprint.
Use it near the front or middle of a sunny border, where its narrow upright form can punctuate lower, broader plantings without blocking a view across the bed. A short run beside a path, patio edge, or bed corner makes the red-tipped foliage easy to see at close range. Keep its planting area distinct from open lawn, naturalized ground, and loosely managed borders so its spread can be watched and addressed.
Allow an 18-inch center-to-center spacing for a connected small-scale drift. Each plant can occupy about a 1½-foot-wide footprint at maturity, so a single row needs a clear strip rather than being squeezed between stepping stones or crowded against larger perennials. Leave a reachable edge along at least one side of the group for division, removal, and monitoring.
Place Japanese Blood Grass in full sun, where its upright foliage has room to stand clear of neighboring plants. Give it moderate water and avoid assigning it to a bed designed around prolonged drought or a site that regularly stays wet. In a mixed planting, group it with plants that can share regular watering without casting heavy shade over the clump.
The red coloration intensifies in fall, so position it where the late-season shift remains visible after earlier flowers fade. Leave enough open space around the foliage for the color and upright outline to remain legible from the path or seating area, and check the clump through the season so any flower heads or all-green shoots can be removed quickly.
The species, Imperata cylindrica (cogongrass), is a federal noxious weed and one of the world's worst weeds, and planting it is prohibited in some states. This red form spreads more slowly but can revert to the aggressive green form, and it is not recommended for planting, particularly in the Southeast. Confirm local restrictions before adding it to a plan, dig out any green shoots immediately, and keep it away from unmanaged edges, woodland margins, and drainage corridors; dry growth can also present a fire risk near a home.[1][2]