Arundo donax Control Project
In 2002, the Navarro Watershed, through the Mendocino County Resource Conservation District was the recipient of a $15,000 Grant from the California Department of Fish and Game for the purpose of removing Arundo donax or Giant Reed, an invasive plant species, from the watershed. The projects’ initial scope was to educate landowners and residents to the presence and the potential threat of this invasive plant to the river system, also, to learn how to identify what it looks like and how best to treat it for removal, and finally, to outline on a map where the present known stands are.
Arundo donax growing on the banks of the Navarro River
Description
Karen Gaffney from Circuit Rider Productions in Windsor visited the Navarro River watershed in March of 2003 to give a slide show and talk to the community about Arundo. She gave us all kinds of information on the plant; from its history (it is from India where elephants graze on it) to where it likes to grow (on the edges of any water source, primarily creeks and streams) also, why it is invasive (it grows like bamboo and so it has segments, each one of these segments can break off and root itself downstream) why it is a problem (because it can end up choking watercourses as it has done in steams all over California as well as creating terrible problems for our neighbor the Russian River Watershed) and finally, she showed us numerous techniques for removal (hand removal, i.e. digging it up, or cutting and tarping in early May and June, or as a very last resort herbicide, cut and paint technique) because as noted earlier usually it’s growing right along the banks of streams or rivers.
Arundo removal in 2003
Arundo donax in the Navarro
We now had a much better idea of the nature of what we were dealing with here and the steps that would need to be taken to effectively manage any invasion of this plant to our watershed. The truth of the matter is, the plant has been here in small numbers for about 12-15 years and has been moving around slowly but surely throughout our watershed. For some reason, whether it be the coastal influence and cooler temperatures, or that our riparian corridors have more tree cover than the heavily infested parts of the Russian River, or simply we are witnessing it on the early end of its move, Arundo has not taken an extreme hold of our stream systems, fortunately. The good news is that we have the opportunity to be proactive and make sure it stays that way.Reasons for Controlling Arundo
The reasons we do not want to see Arundo or Giant Reed invade our water system are: It uses about 5x's as much water as native plants, it is extremely flammable and can put our riparian zone and property in risk of fire, it is true that it was planted as bank erosion control years ago but it can actually easily dislodge in floods and clog up watercourse flow, it has no habitat or food value to native wildlife except for nesting wood rats. Finally, as all invasive plants do, it can push out and out-compete the native vegetation.
Arundo removal in 2003
Project Development
We began by identifying as many sites as we could find and getting them mapped with GPS coordinates with the aid of Rixanne Wehren from Geographics in Albion. We contacted landowners and asked them to participate in the removal project and finally, where we were granted permission, we went in with crews of 2-5 people and worked anywhere from 3 hours to 3 days depending on the size of the clump and the follow-up prescriptive treatment. Joe Scriven from E-Center in Ukiah wrote a lot of the prescriptions for the removal and he and his crew came in and helped on several removal sites.The Methods We Used in the Navarro
We primarily used the cutting and tarping method in which you cut the stems of the Arundo in May or June at roughly 2-6 inches above ground and then you cover with thick plastic tarps and you staple down the edges with irrigation staples to keep all light out. The idea is to kill the plant by cutting off its' ability to photosynthesize and halt the growth process. It is a very effective means of removal. By fall, the plant should be dead and the tarps can be removed. If the clump is not on the edge of a watercourse and the tarps can stay on through fall, it does not hurt to leave them on until spring.
Arundo root mass removal in 2003