Let’s talk about plant invasions. You know the story. Spores of alien plants fall to Earth in meteors. The terrifying plants then stalk and attack mankind (Figure 1).
Well, okay. Our plants are not from outer space, and they don’t eat people. However, these plants are invasive and wreaking havoc on our ecosystems. They choke out our native plants and animals, and they could be in your back yard right now. So what can you do?
A plant is considered invasive when it’s been taken out of its natural environment and transported to another where it is no longer controlled by its natural pests, diseases, climate, etc. They then grow unchecked and outcompete native species. Invasive plants can be introduced by accident but some are brought deliberately. The real question is how we get rid of them when they become a problem.
The first one on our list is the Multiflora Rose. Sounds pretty, but if you’ve ever walked through a patch of it, you know it’s not. They are member of the rose family, and the Midwest does have native roses. These however were brought to the U.S. from Japan in 1866 as root stock for domestic roses. Later in the 1930s, they were used for erosion control and as living fences¹. Now, it crowds forest floors and grasslands, and can alter nesting behavior of our native birds.
They have long arching branches (canes) that are covered in thick thorns (Figure 2). These canes are green when they are young, but turn brown with age. Cane tips can even root if they touch the ground. It has 5- petaled white to pink flowers (Figure 3) which mature into small, red fruits that are spread by wildlife. To get rid of them, you have to cut the canes off at the base and paint with glyphosate or triclopyr. You can also mow with a brush cutter repeatedly, but they do try to grow back1.
Another invader is Garlic Mustard which came from Europe and was probably introduced in the early 1800s as a food source. You can tell garlic mustard by its strong garlic smell. It has a two year life cycle, a rosette and then the second-year plant. Rosettes are kidney shaped with scalloped edges, and unfortunately can be mistaken for natives like violets (Figure 4).
The following year, these rosettes bolt quickly into tall plants that flower (Figure 5). The problem with this plant is that it shades out our native forest plants like our wildflowers (See March 20 post). This affects our native butterflies and any other species dependent on our native plants. To get rid of it, you cut it below ground level, spray it with herbicide, or pull it up1. It is best to get rid of these plants early before they flower or set seed, and you have to monitor and pull the site for several years.
The last we’ll cover for today is Honeysuckle. There are many species and varieties, but we’ll cover Bush Honeysuckle. It grows like crazy, crowds out our natives, alters ecosystems, and is very hard to eradicate. It was brought to the U.S. in the late 1800s as an ornamental and was promoted for wildlife. It can grow 6-20 feet high and flowers during May and June with white flower that fade to yellow (Figure 6).
Honeysuckle leaves are opposite each other and smooth edged. Their fruits are bright red (Figure 7) and often spread by birds¹. To get rid of it, spray herbicide on the leaves in the late growing season or cut the large stems and painting with herbicide. You may have to do this a couple time. If you just cut down the honeysuckle it will resprout several new growths, like a hydra.
The first step in fighting invasives is identifying your plant. This can be tricky, but there are plenty of books, and even websites. Check out www.weedid.wisc.edu for help identifying some common invasives you might run across. With this website, you will need to know how to identify certain parts of a plant such as leaf shape and branching pattern.
For help with these and other plant identifiers see this Plant Identification Basics guide. Even with great resources, it can be difficult to ID a plant online. It never hurts to contact a specialist. For pest specialists in your state visit the Pest Tracker website, which covers animal pests as well as plants.You can even use the Ask an Expert tool where you can write your question and upload photos.
Another way you can be part of the fight is planting native plants in your yard and garden instead of exotic non-natives. If you would like to know more about native gardening and landscaping, I suggest reading my blog post “Oh the Flowers You’ll Grow” from May 27, 2015. Be sure to check back in February 19 to read about some local plant warriors, and what they are working on to protect our native ecosystems.
- Kaufman SR, Kaufman W. Invasive Plants Guide to Identification and the impacts and control of common North American species. Machanicsburg, PA: Stackpole Books; 2007.