Check out our newest video How to Kill Invasive English Ivy Vines: 3 Steps. If you like PowerPoint presentations better, here it is: PowerPoint How to Kill English Ivy Vines. We will be publishing another set of presentations on killing English ivy groundcover. For that we recommend a foliar or wipe application. English ivy can be a real problem in many parts of the world. It can climb tall native trees and eventually even kill native trees. As a groundcover, it also can out-compete natives. One thing: English ivy can be controlled in the winter when many native plants are dormant.
At Green Shoots, we sell concentrated weed killer and our foam herbicide dispenser systems help you
apply that weed killer precisely and with low drift. Concentrated weed killer or herbicide is not just more economical. It is also more effective.
Read this paper (link) from Bryan Young, currently a professor at Purdue about glyphosate rates. In it he says: “The most consistent application factor that can increase glyphosate efficacy is lower carrier volumes.” What does Professor Young mean by this? He means that by adding less carrier (i.e., water) and increasing the amount of glyphosate herbicide (i.e., increasing the herbicide concentration) in the spray solution, the herbicide is more effective. Moreover, this is the case even though an application may cover less of the target plant.
Take a look at the photos below and this video to see before and after images of weeds treated with low volume/high concentration applications: Video (link). As you will see in the foliar applications, very small amounts of herbicide are applied to very small areas of foliage (probably covering less than 10% of the green foliage). In spite of the small amount of coverage, the weeds were completely killed.
This presentation at the Upper Midwest Invasive Species Conference, 2014, summarized some of our control work on invasive knotweed at Southwood Nature Preserve in
the Twin Cities Metro area. It also briefly discusses use of our foam herbicide system by the Northeast Iowa RC&D where they have had success treating a large infestation of greater than 25 acres. Finally, Washington State
University did some testing this summer comparing our foam herbicide dispenser to traditional spraying techniques. So far (and these results are very preliminary), the foam herbicide has performed better than the spray even though half as much herbicide was used on the plots where foam was applied. The full presentation is online at: How to Kill Japanese Knotweed.
As soon as we get data from Washington State University on their testing of the foam system, we will provide a link or other information.
We just added a new page with testimonials about our products. Here it is: Testimonials (link). They will give you an idea about what people are doing with our foam herbicide dispensers!
We launched our new website: Green Shoots. We have several new products on the website: our Large Foam Herbicide Dispenser; Foaming Agent; and Aquatic herbicide. If you are a professional or have a large piece of property with invasive weeds, you may be especially interested in our Large Foam Herbicide Dispenser.
We will also be adding a resource center in the near future. This will give you a link to our videos and other postings.
In about two weeks we hope to have our new website up! We will offer several new products including the Large Foam Herbicide Dispenser. This product will be especially useful for the professional or non-professional who has a big invasive weed project.
We will also be offering an aquatic herbicide and a foaming agent. The aquatic herbicide will not have manufacturer-added surfactants. This will allow the user to add a surfactant of their choosing – for example, our foaming agent which will be a mild, non-ionic surfactant made from plant-based materials that are readily biodegradable.
As someone working for company that sells herbicide for killing invasive plants, I get push-back from people who don’t like to use herbicides. This is understandable. When herbicides are used almost indiscriminately – killing both weeds and desirable plants, that is a huge problem. Researchers have, for example, found a loss of milkweed in agricultural fields due to increased herbicide use. Lower milkweed populations means declines in monarch butterfly populations. Pleasants et al. 2012.
If herbicides are used with precision, however, I find they can be enormously useful. For quickly eliminating harmful invasive weed trees such as buckthorn, they are indispensable, especially if you are working on a large scale. After reading numerous scientific articles over the years, I feel comfortable using them. But, I certainly respect the decision of those who choose not to use herbicides.
If you decide not to use herbicides, what is the best way to kill a weed tree? It will be tougher, and it will take at least a couple years to accomplish, but it can be done if you have patience and the number of weed trees is limited.
Here are some tips. First, don’t concoct homemade herbicides. Many people think, for example, that pouring salt on a plant is better than using a commercial herbicide. From an environmental perspective, however, you are doing much more harm than good. Herbicides like glyphosate bind tightly to soils and break down relatively rapidly. Salt, on the other hand, is very persistent in soils, and most plants do poorly in soils with high salinity. Read this article from the University of Illinois about homemade herbicides if you are tempted.
Second, be careful if you decide to pull weeds, especially large weed trees. Not only can you strain your back, you can also hurt nearby desirable plants by uprooting them. Also, freshly disturbed soils invite weed seeds. Try to minimize disturbance of soils.
Especially with weed trees, one technique I have used is repeated cuttings to weaken a plant. Timing is critical. The weed trees shown in the photo above – common buckthorn, for example, were trimmed back to what I call “tall stumps,” i.e., stumps that are above waist height or even taller if possible. I did this in the spring after they had fully leafed out. This is the time of year when the tree has sent energy from the roots to the foliage for leafing out and flowering. It’s also a time when plants are normally vigorously photosynthesizing. By trimming off all the foliage you have not only robbed a tree of much of its stored reserves, you have also harmed the tree’s ability to photosynthesize during a critical time. (You have also prevented the plant from flowering and creating seeds, which is why I trimmed these trees.)
Most invasive trees will recover. For example, buckthorn will regrow branches after a cut as shown in the photo above. The reason for cutting the tree high is two-fold. First the tree will generally grow new branches as high on the stem as possible. To weaken the tree still further, you should do another cut just below that new growth. Ideally that cut should be made in the same year – after the tree has expended energy in forming new branches. Second, another reason for cutting high and creating a tall stump is to avoid creating a bush. If you cut a stem close to the ground, multiple stems will grow from the stump. You now will have to cut multiple stems rather than just one.
It is surprising how much a well-timed trim will weaken a weed tree. I have noticed that if I top a seed-producing buckthorn it may take several years before that tree produces seeds again. In addition, I often find the sapwood of these topped trees to be discolored. This indicates to me that the tree has been stressed.
The above technique also works well even if you decide ultimately to use an herbicide. Applying an herbicide in the spring when sap is rising is generally a bad idea. By trimming and forming a tall stump in the Spring, you have eliminated at least one year of seed production. You have also weakened a tree ahead of the herbicide application and made the success of that application more likely.