In 2011, UW-Platteville geography students, Nick Flinner and Abbie Lehman, were trained in detection of invasives and completed a full scale assessment of the watersheds, locating instances of Japanese Hops. In addition they recorded instances of other invasives to include: Eurasian Bush Honeysuckle, Garlic Mustard, Multiflora Rose, Wild Parsnip and Canada Thistle. The students conducted field work by wading and canoeing the rivers to find invasive plant species. With the gathered information, the students developed a numerical classification system in order to present the information in a map format. They used a system with a class of I-V, “I” being the least severe and “V” being the most severe. The level of infestation was measured by number of plants per meter for plants with stalks, and percent coverage for vine-like and groundcover plants. Using a Trimble Juno GPS unit equipped with ESRI ArcPad, the students collected points of invasive species and the course of the river in the field. Once back in the lab, they digitized the severity of the infestation using various line representations, each indicating the spatial severity of the infestations. With this data, the students then made a map for each of the invasive species found on the rivers. This project provided the students an opportunity to work with top-of-the-line field mapping equipment as well as the experience of working as independent contractors for a non-profit organization. Ultimately, future students at the University of Wisconsin-Platteville can easily build on these maps through continued research in the Platte River watershed.
Concerning eradication measures on the state managed lands:
Chemicals: Garlon 3A- triclopyr; Escort- Metsulfuron; Rodeo- Glyphosate
Plot size: 9M x 9M
Plot number: 24, all of the 12 methods were duplicated
Results per Method
Cutting- Using a weed eater, this method was shown to be ineffective because it only took a few days for the hops to grow back to a size that was comparable to the control.
Hand Pulling- Ineffective, labor-intensive, and time consuming as proven by the River Spirit Exchange where ~40 people were pulling hops for 2 hours and a month later it had grown back. Suggested for land owners who have a small infestation and have the ambition to hand-pull when the plant is identified.
Tarp- Effectively killed the hops. Seed bank is not affected. This method would have to be repeated annually until the seed bank is used up (3+ yrs).
Garlon 3A- Early Summer- Killed 100% of the hops, but by the end of the summer reed canary grass started to grow.
Garlon 3A- Early & Late Summer- The early application caused 100% kill. No need to re-apply. By the end of the summer, reed canary grass started to grow.
Galon 3A- Late Summer- Killed 100% of the hops, by the end of the summer nothing had started to grow.
Escort- Early Summer- Caused 100% kill, by the end of the summer there was still no vegetation trying to reestablish a population.
Escort- Early & Late Summer- Spot treated a few Japanese hop plants that were starting to emerge. 100% kill with no regrowth by the end of the summer.
Escort- Late Summer- Did not kill all of the Japanese hops. ~70% kill. Most of the plants were wilted, yellow and on the ground. These plants were too ill to produce seeds, thus, still an effective time and method.
Rodeo- Early Summer- Killed 100% of the Japanese hops but new hops started to grow. A few blades of reed canary grass were also evident.
Rodeo- Early & Late Summer – Killed 100% of the Japanese hops, by the end of the summer reed canary grass was starting to grow.
Rodeo- Late Summer- 100% kill. No regrowth.
The seed bank is thought to only be three years so if a plant infestation is eradicated before it goes to seed (August-September) for three years, complete kill will be accomplished as long as seeds are not reintroduced via flooding, mowing, or any other sort of seed transportation.
The three chemicals used were all pretty effective with one application, but a follow-up spot treatment might be necessary. Since the hops tend to grow on or near river banks, all of the chemicals are aquatic approved and are safe to all of the organisms living nearby.
To reproduce the tarp method, use a black tarp, 4 fence posts, zip ties and some rocks. Tie the tarp to the posts so it is resting on the ground with the zip ties and weigh the tarp down with a few sizeable rocks. Leave the tarp in one spot all summer & make sure the tarp covers the entire population. Caution: water can pool on the tarp and create a habitat for mosquitoes.
Future Work:
The future work plan for addressing Japanese Hops in the Platte/Little Platte watersheds should be focused on the most isolated and upstream portions of the Platte River main channel as indicated on the enclosed map. One of the effective chemical applications should be used in a consistent three year application to eradicate these populations. Success on the Platte River will be followed by addressing upstream and isolated populations on the Little Platte River using the same chemical methods. High concentrations downstream populations on the Little Platte River and tributaries should be the final areas of concentrated efforts.
