Japanese Barberry is a plant native to Japan, and it goes by the scientific name of berberis thunbergii. This plant is a known invasive, and in this article we will talk about how to get rid of Japanese barberry in your yard.
In the late 1800s, it got introduced to the United States, where people used it for decoration in places with high numbers of deer. Deer feed on landscape material and can affect the aesthetics of the surroundings. People realized that though deer fed on native species, they were unable to do the same to the Japanese Barberry. And hence, this plant became commonplace in many outdoors. You have probably come across it at some point or the other.
Given that the Japanese barberry is not native to the states, there were some variations in how it grew. For one, it would leaf out early, and the leaves would remain in place during fall. The native plants could thus get some shade from the Barberry and would require less care. It was another reason behind the popularity of this plant. After all, if a shrub can reduce the work needed in gardening and is easy on the eyes, wouldn’t you want it?
Another thing that stood out with this plant was its ability to survive in diverse conditions. It could do well in both shaded and non-shaded conditions. Whether you had it in the woods or had it out in the open, it thrived. And this significantly reduced maintenance practices in the yard.
With all these benefits, one would want to have this shrub in the yard. But wait, not so fast. Over time, it became clear that this plant could be harmful to both the environment and the people in the surroundings. After years of research, scientists established a relationship between Lyme disease and the Japanese barberry. It turns out that these shrubs host higher densities of white-footed and deer mice, and adult deer ticks as compared to the native species. And these adult ticks present a threat as they contribute to the spread of Lyme disease.
Where these shrubs are in small numbers, the number of mice and ticks present are few. Control of the Japanese barberry is therefore imminent to prevent the spread of diseases.
How to Identify Japanese barberry
These deciduous shrubs are spiny with branches that arch out. They stand at about two to three feet, but in ideal conditions, they can be as tall as six feet. Their leaves are small, with spoon-like shapes and smooth margins. They arrange themselves in clusters and turn red during fall.
The stems arch, as is the case with the branches, and they have deep grooves in them. At each node, you find single spines. When the twigs are young, they have reddish-brown hues in the cold months. The older parts of the stem remain grey.
Their flowers bloom in April and May and are quite small and yellow. They dangle on the branch, with clusters of about six petals.
The fruits produced are equally small, with bright red hues and dry flesh on the inside. Deer and birds disperse these fruits, encouraging the growth of more shrubs.
Why is Japanese barberry invasive?
These plants can adapt to different soil types and climatic conditions. When they take root, it takes a lot to control and get rid of them. A good example would be Minnesota. Where these plants take root and grow with minimal control, they can form large thickets that are almost impossible to penetrate. Given that these shrubs have proven to have adverse effects on the people living in areas where they are in large numbers, controlling them is of the essence.
How do the bushes spread?
The Japanese barberry has bright colored seeds that birds and deer spread through pollination and feeding on them. Other than this, where the bushes have low branches, the branches can root upon contact with soil. Plus, people cut them and plant them in different areas, leading to their spread. Remember that once they take root, they thrive, and controlling them becomes a problem.
Effects of invasion
Not only can they make landscaping an uphill task, but they also affect the economy and the balance in the ecological system. Have you ever heard of plants that can change the chemistry of soil? There are the nitrogen-fixing plants, which you have probably come across. And then there are these Japanese barberry shrubs which fix the soil to make it conducive for their growth. The nutrient levels increase in the surrounding ecosystem, and the pH of the soil changes.
With these effects in place, the Japanese barberry shrubs increase in numbers while the native plants reduce. Remember that deer cannot feed on these shrubs, and they thus resort to eating native plants, further reducing their numbers. After a while, you realize that the shrubs have taken over an area. And that’s not all; they also limit the movement of animals by creating impenetrable and thorny thickets.
When Japanese barberry shrubs are in large numbers, they play host to ticks and mice, which can cause tick-borne diseases such as Lyme disease. They thus pose a risk to livestock, pets, and human beings.
How to get rid of Japanese barberry
The Japanese barberry looks great and would add beauty to a landscape. However, when left in uncontrolled conditions, they can become a menace. One which not only threatens other plants in the area but animals and humans as well. Where it is clear that they are out of control, here are some methods to get rid of Japanese barberry:
Prevention of Seed Production
Though these plants can also grow from low-lying branches, their main means of propagation is the dispersal of seeds. It would thus help to prevent the production of seeds, which would put an end to the dispersal. How can you do this? It starts with the identification of isolated plants and getting rid of them before they have the chance to produce seeds. Isolated plants are a result of seed dispersal, and getting rid of them would be nipping the problem in the bud. Get it?
Note that the removal of isolated plants does not mean that they will stop growing indefinitely. With the plants out of the site, there will be added light, which would encourage the growth of other Japanese Barberry plants. In the seasons that follow, you should keep an eye on the site to deal with any outbreaks.
You can use three methods to get rid of Japanese barberry: chemical, manual, and mechanical. You will note that there is no biological solution to this, which would appeal most to people who are into green-gardening. Burning, which has adverse effects on the environment, has also proven to have little impact on the Japanese barberry. The method you choose depends on the extent of the invasion as well as what appeals most to you. Let’s get started:
As the name suggests, this is a hands-on approach, and you will need some gloves and clippers for this. It involves pulling out seedlings as well as mature shrubs. Where the shrubs are wanted but are getting out of control, you can choose to clip them to limit their growth. Another alternative would be to mow them now and then. When cutting them, do so as near the ground level as is possible as this will reduce their growth rate. It is important to note that this is not a permanent solution to get rid of Japanese barberry, and it only works in keeping the shrubs low.
Choosing to deal with the shrubs by hand can be difficult, and it takes time to do so when dealing with large bushes. Where the bushes are small, you can pull them out. This method is also ideal for areas where herbicides are not a welcome option.
Japanese barberries have shallow roots, and pulling them out when they are young should be easy. It helps to wet the soil before pulling them as this makes the removal process much more manageable. Also, it reduces the number of root fragments left in the soil, as these can re-sprout and cause another outbreak.
Where the Japanese barberry bushes are in large numbers, you can combine mechanical removal with other methods such as the use of chemicals to better deal with the problem. Once the site is clear, limit soil disturbance as this can encourage re-sprouting.
The plants’ parts should get disposed of in a way that does not encourage propagation. Ensure that the roots are completely dry before getting rid of Japanese barberry plants. You can burn or bag them and place them in a landfill where they cannot get ideal conditions in which to thrive.
Fall is the best time to use chemicals on the Japanese barberry. During this time, native plants are dormant while the non-native ones, such as barberry bushes, are in active growth. Targeting the bushes at this time would limit adverse effects on the native plants. It owes to the ease of visibility of the green leaves while other plants have turned brown, shed leaves, or some other change. You can, therefore, be generous with the chemicals without fear of damaging other ornamental plants in your yard.
If you are unable to carry out the chemical application in fall, you can do so in winter, as it has proven to be an ideal season too. When choosing a chemical, think of how it could affect the native species and make a choice accordingly. Also, think about the potential for erosion and how close the shrubs are to a water source.
You can use some additives with herbicides to make the process much more effective. A good example would be the addition of dyes to the chemicals to help you keep track of the treated plants. It would also alert you if you got some of the chemicals on your clothes. Before using any chemical, read through the instructions to make sure that you apply it efficiently. Below are some of the treatments you can consider to get rid of Japanese barberry:
You can use this treatment where Japanese barberry bushes are in plenty, and there are few natives on the site. Wait until the plants are actively growing, and the sap flow is heavy. If there is a lack of water, the application may not work as expected.
The herbicide usually used to control Japanese barberry is glyphosate. It can be used to control a single plant or a large area. For foliar treatment, a 2% solution of glyphosate and water is effective.
The herbicide’s manufacturer will indicate how much of the chemical you should use and over what area. The instructions should also cover the ideal weather conditions and how you should go about the application to prevent drift and volatility. Once you treat the shrubs, you should let them grow for a full season without cutting them down.
In this treatment, you should cut the stem as near to the ground as is possible. Ideally, this should take place late in the growing season when there is transport of nutrients to the roots. Thus, schedule the cutting between August and October. If you miss this period, you can opt to have it done at another time- so long as the sap is not flowing upwards. When cutting, ensure that you do so to the ground level. Else, you will leave enough room for sprouting, and you will end up repeating this process.
Apply a herbicide mix to the stump, a 20-25% solution of glyphosate or triclopyr with water will work great to prohibit further growth of the shrub. Do not let time pass between the cutting and the application, as this could encourage growth.
Basal Bark Treatment
With the two methods above, there are restrictions as to when the treatment can take place. If you miss the timelines above, you can use this method, which is applicable as long as snow levels are not limiting. If you can spray to the ground level without getting hindered by snow, you can use this method.
Apply a mixture of 25% triclopyr and 75% horticultural oil, and keep spraying until you see a runoff on the ground. You cannot use this method when the weather is rainy, as this will wet the bark and undermine your efforts.
All the best of luck in eliminating unwanted Japanese barberry bushes from your yard!
- Invasive Species—Best Control Practices – https://mnfi.anr.msu.edu/invasive-species/JapaneseBarberryBCP.pdf
- Japanese Barberry – https://www.mda.state.mn.us/plants/pestmanagement/weedcontrol/noxiouslist/japanesebarberry
- Brush Management– Invasive Plant Control Barberries – Berbis sp – https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs144p2_015219.pdf