Arundo donax, also known as giant reed, Georgia cane, or carrizo cane, is a very large and aggressive exotic grass that is multiplying rapidly in some Texas riparian areas. This species was introduced into North America many years ago for erosion control and has been widely used in highway right-of-way plantings. Like many other exotics, it does not stay where it was planted. The large spreading rhizomes allow for quick enlargement of existing plants. Apparently the seeds are sterile, but the stems and rhizomes, which become dislodged in floods, will float downstream and start new plants where they land.
Arundo is considered a major invasive pest in some states because of its ability to monopolize riparian areas. Not only does it spread quickly, but it can dominate to the exclusion of native riparian species. I have noted scattered colonies of Arundo along creeks for many years, but did not become concerned until recently.
Sky Lewey, with the Nueces River Authority has been watching the distribution of Arundo on a short reach of the Nueces, north of Uvalde. She noted the first occurrence of it in 1997, and has watched it grow from a single plant to several large colonies in just ten years. More alarming is her observation that the Arundo colonies appear to envelop and kill sycamore, and displace other native riparian plants. The colonies are now far too large and numerous for small scale removal techniques.
Arundo is not to be confused with the native Phragmites communis, or common reed. The two species do look somewhat similar, but the native Phragmites is a desirable component of riparian vegetation.
In some situations, both species can be found growing together. Arundo is the much larger of the two in every respect. A quick image search on Google will provide numerous photographs of each species if needed. Here is a comparison of key features.
|Total heightLeaf width
|10 – 20 feet1.5 – 3 inches
1 – 2 inches
|6 – 12 feet.5 – 2 inches
.25 – .5 inches
Arundo control is being advocated in some areas. The most effective method being used at this time is herbicidal application with a helicopter. Two effective herbicides that are labeled for Arundo control are Roundup (glyphosate) and Arsenal (imazapyr). The aquatic-labeled formulations of these herbicides are Rodeo and Habitat. Burning or other removal of the old dead growth is sometimes suggested to get more herbicide on active leaf tissue. Late summer application is recommended to maximize translocation to the massive rhizomatous roots.
Your assignment is to take note of where you see Arundo colonies. If possible, measure or estimate the growth of those colonies over time. Take note of its impact on native riparian vegetation. It is always easier and more successful to manage invasive species before they totally dominate large areas. No need to declare jihad against Arundo but it is wise to take action before it becomes an insurmountable problem.
Steve Nelle, NRCS