The Japanese Bloodgrass – Cogongrass Connection

Joey Williamson, Ph.D.
Home & Garden Information Center

Japanese Bloodgrass (Imperata cylindrica) is a 2 foot tall perennial grass with red and lime green leaves. Sales of this grass have been halted in South Carolina, but plants have been brought in from other states. Although this grass might make a nice colorful addition to the perennial garden, its highly aggressive nature warrants us to think twice about planting it.

Japanese Bloodgrass, a variety of cogongrass
Japanese Bloodgrass
Steve Compton, Clemson Dept. of Plant Industry

The problem is that Japanese Bloodgrass (or Red Baron Grass) is a variety of cogongrass, one of the world’s ten worst weeds. This red-leafed ornamental grass can revert back to the extremely aggressive, 4-5 foot tall green form, which has already invaded 153 billion acres worldwide. Cogongrass is becoming established in Florida, Georgia, Alabama, Mississippi and Louisiana, and has now been found in South Carolina. In Florida alone, it has infested one million acres, where it has displaced many native species of plants.

Cogongrass will invade pastures, where it reduces the forage quality because its leaves are unpalatable to livestock. It can quickly displace other vegetation in forests and fields, including native plants that birds and small animals need for shelter and forage.

Cogongrass in bloom
Cogongrass in bloom
Steve Compton, Clemson Dept. of Plant Industry

This weed spreads not only by an aggressive root system, but by seed heads that produce an abundance of wind blown seed in the early summer. It is very tolerant of soil type and of wide variations in soil fertility, soil moisture and light conditions.

Fluffy seedhead of cogongrass
Cogongrass seedhead
Steve Compton, Clemson Dept. of Plant Industry

For gardeners who would really like to have a red-leafed ornamental grass in their perennial beds, there are other choices. For example, there are three cultivars of our native Panicum virgatum called red switch grasses that have red foliage, and are especially prominent in the fall.

Red switch grass, a native alternative to Japanese Bloodgrass
Panicum virgatum 'Shenandoah'
Erv Evans, Consumer Horticulturist, NCSU

‘Shenandoah’, ‘Squaw’ and ‘Rotstrahlbusch’ are non-invasive red switch grasses for sunny gardens and adapt to a wide range of soil conditions. ‘Shenandoah’ looks the most like Japanese Bloodgrass, as its foliage starts out green with the tips turning red in early summer.

Clemson University’s Department of Plant Industry is a member of a task force, which includes the SC Forestry Commission and the US Forest Service, with the goal of preventing the spread of cogongrass in South Carolina. If you have Japanese Bloodgrass or have seen cogongrass in your area, please contact Steve Compton at the Clemson Department of Plant Industry at 864-646-2130. Any sighting will be investigated, and hopefully we can stop the invasion of cogongrass.

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This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.