Cogongrass Research Paper

WANTED
Dead not Alive:

Cogongrass (Imperata cylindrica) has become a major problem for landowners, land managers, foresters, and governmental agencies since its introduction into Alabama. Known to many as japgrass, cogongrass was accidentally introduced into Alabama near Grand Bay about 1911 as seed in packing materials from Japan (4). Purposeful introductions soon followed in other areas of Alabama, Mississippi, and Florida, with the primary intent for forage production (1,4). Horticultural varieties of cogongrass continue to be sold under the name Japanese bloodgrass or Red Baron grass, although illegal in the state of Alabama. Infestations of this perennial grass from Asia forms exclusive colonies, displacing native vegetation with the
exception of mature trees (5). In addition, cogongrass is a fire adapted species, meaning that it thrives where fire is a regular occurrence (1,4). As a result, cogongrass burns hot and readily, creating safety and property loss concerns. Wildfire in cogongrass can kill mature and seedling trees and native plants, furthering its domination. Rights-of-way managers loathe cogongrass for its unsightly growth habit, difficulty in mowing, and displacement of more manageable species.
Cogongrass spreads by both wind-blown seeds and underground creeping rhizomes. The rhizomes can form a dense mat in the upper 6-8 inches of soil and may comprise as much as 80% of the total plant mass (1,2). It is the rhizome system that makes this plant particularly hard to control. Elimination of aboveground portions of the plant can be easily accomplished, but if the rhizomes are not killed or removed, rapid re-sprouting and regrowth will occur.
Conservative estimates put the infested acreage between 500,000 and one million in Alabama, Mississippi, and the Florida panhandle. In Alabama, cogongrass has been found in 32 counties and as far north as Winston County (see map). Regionally, cogongrass can be found throughout Mississippi and Florida, and in scattered infestations in Georgia, Louisiana, S. Carolina, Texas, and Virginia. Once cogongrass gains a foothold in an area, its just a matter of time before it spreads from the infested site. Therefore, IT IS VERY IMPORTANT TO RECOGNIZE AND ELIMINATE COGONGRASS BEFORE IT SPREADS FROM AN INFESTED SITE, AND UNDERSTAND WAYS TO PREVENT ITS MOVEMENT AND INTRODUCTION.
IDENTIFICATION
Cogongrass has some distinctive vegetative features that aid identification.
Cogongrass rarely is found as a single plant but quickly forms patches or infestations, often circular in outline. Plants vary in height, even in the same patch from 1 to 4 ft. tall (1,5). Taller leaves will lean over in late summer. Leaves measure -1 inch in width and are commonly 12-30 inches long. They rarely have a lush green color; instead, they appear mostly yellowish green. A reddening of the leaves sometimes has been observed in the fall, and is correlated to extreme changes in temperature. The whitish upper midrib of a mature leaf is often not centered on the blade as with most grasses thus making identification somewhat easier. Also leaf margins are rough to the touch due to tiny saw-like serrations, which is a common trait of other grasses as well. It is this rough margin, which may cut the tongue of a grazing animal, along with a high silica content that make cogongrass a useless forage crop. The leaves appear to arise directly from the soil, giving the impression that the plant is stemless, but short stems are present. A few short hairs may arise at the node, or the place where the leaf arises from the stem, but otherwise the plant is
hairless.
Another key identifying feature is the production of fluffy, white, plume-like seedheads in early spring. This spring flowering is contrary to most summer grasses, which flower later in the season. Cogongrass also has been documented to initiate flowering at other times of the year in response to disturbance such as herbicide application, fire, mowing, or the first hard frost (4). Seedheads range from 2 to 8 inches in length and may contain as many as 3000 seed. Each seed has silky, white hairs that aid in wind dispersal. Seed viability is variable and seed must land on bare ground for germination (3). Rhizomes of cogongrass are white, segmented and branched and have been found extending 48 inches below the soil surface, but more commonly completely occupy the upper 6-8 inches (2,5). Rhizomes are sharp-pointed and often pierce the roots of other plants and unprotected human feet and hands. Each rhizome segment can give rise to a new plant, which can occur with cultivation or partial herbicide control (4).