6 “Must-Knows” About Japanese Barberry
As the temperatures get warmer, if you’re here, you’ve undoubtedly begun to think about what you’re putting in your garden this Spring. One plant to watch out for is the Japanese Barberry (Berberis thunbergii).
This easy-to-spread invasive species originates from Japan and has been in the U.S. since 1875. The plant was first introduced as seeds to the state of Massachusetts and in 1896 was planted in the New York Botanic Garden. 
Originally the barberry shrub was seen as an excellent substitute for the European Barberry (Berberis vulgaris). The European version was originally used for jams and dyes, throughout much of the U.S.
It would be later discovered that this same popular version of the plant was a host for the Black Stem Rust found in the wheat crops. Looking for an alternative, the Japanese barberry was believed to be a positive solution to the problem of the European variety. Little did science know, this species would become one of the most invasive plants in the U.S.
1. Invading Your Space
Unfortunately for us, invasive species don’t currently have a ranking system, as they’re all very invasive. But, we’d bet our bottom dollar that chances are if there was a list, this plant would be at the top of it.
Japanese barberry currently can be found in 31 of the 50 United States of America.
As this plant is invasive to North America, it is quite literally invasive, everywhere that it grows throughout the U.S.
What makes Japanese barberry invasive isn’t just its ability to rapidly spread, like wildfire. But, the plant is a woody plant variety that overcrowds the native plants of our landscapes compromising various natural ecosystems throughout the U.S.
But, if that wasn’t enough, the species has adapted favorably to North American conditions and has proven incredibly resistant to biological controls that normally evolve to combat a plant like this.
Normally diseases and other plants would adapt to drive out the invasive plant biologically, but due to the resistance of the Japanese barberry natural competition and biological controls have been unsuccessful.
2. Where It’s The Worst
From what we’ve told you so far, the barberry invasion occurs in 31 of the 50 states throughout the U.S. But, that doesn’t mean that the invasive threat is the same in all 31 of those states.
Throughout the Northeastern part of the U.S. Japanese barberry is one of the most invasive plants in their environments. In states like New York, several cultivars of Japanese barberry are banned from sale and distribution to the state.
From Maine to North Carolina, these evergreen shrubs displace many of the herbaceous and woody natives in their area and wreak ecological havoc. Within these states, growers and sellers can expect a zero-tolerance policy to any possibility of Berberis thunbergii crossing their borders.
But the toxicity of the spread isn’t limited to just the Northeastern portion of the U.S. Throughout the Midwest forested areas also struggle with the rapid spread of the Japanese barberry. The result too is heavy restrictions and education efforts to continually combat the invasive variety.
3. The Damages
We’ve mentioned it a few times already, Japanese barberry has some serious adverse effects on their environments in the U.S. But it isn’t just crowding out natives, and being resistant to eradication efforts.
The cost to remove these plants from public and private landscapes ranges from $100-$200 per acre. This doesn’t include treatment or mechanical costs for removal.
Japanese barberry is causing American taxpayers and landowners millions of dollars to control and remove.
In addition to all of the terrible things we’ve already mentioned about this plant, the leaf-litter from these plants, in large enough quantities, can change the pH level of the soil below them.
Collectively, the Japanese barberry can change the environment by making the soil more basic through its foliage, crowd out native plants, and resist eradication efforts through biological factors.
But if the biological effects weren’t enough, there’s even more damage that this invasive causes! Researchers have identified that areas with dense Japanese barberry populations also have a strong presence of black-legged ticks, known for transferring Lyme disease. 
4. Flight of the Berries
As with any invasive species, there are going to be challenges in removing the invasive from the environment. But, one challenge that makes removing this invasive from environments especially unique is how quickly it can spread.
Japanese barberry grows bright red berries amongst their leaves as a part of their “bloom.” And as luck would have it, birds really love these red berries!
One of the biggest challenges in preventing the spread of this species is that birds often eat the berries when they’re ripe and when they fly they poop the berry seeds back out and disperse them unknowingly.
Other animals also enjoy the berries of this green leaved shrub and contribute to the spread of their seeds. This has allowed the spread of this invasive to make its way from its origin of the Northeastern part of the U.S. all the way to Washington state.
5. Goodbye and Good Riddance
As we’ve explained there are challenges in removing this invasive species. Generally speaking, it could have been expected by now that a disease would have come along and afflicted the species weakening its viability.
Or perhaps evolution would have taken a stronger hold and natives within their heavily afflicted environments would have developed stronger resistance to the plant. But it appears that neither has occurred.
So, how do you get rid of the Japanese barberry?
While the plants are young, they can be removed by hand. But, as the plant continues to grow the removal process becomes more difficult. Due to the sharp thorns of the plant, gloves should be worn to try and remove the plant by hand.
According to the PennState Extension office, removal of the plant can be accomplished by lawn mowing, but professional equipment is required. As a pretty tough plant, even smaller varieties are not easily mowed over. 
Professional equipment will give you the power you need to be successful. The Extension office also recommends mowing the plant, should you choose this method, be done 3-6 times a year to successfully kill the plant.
The Japanese barberry can also be dug up and pulled out, but also require additional treatment once the plant is removed. PennState Extension recommends Dicamba, 2, 4-D or triclopyr for foliar herbicides. They also recommend that in late August and early September that glyphosate and triclopyr can be used on the stumps and branches of the plant as treatments.
At Plant Sentry™, while we support these recommendations, we encourage you to reach out to a professional for consultation and abide by legal labeling requirements.
It has also been identified by researchers that propane torches are an excellent tool in combatting and treating this plant. In areas where herbicides are restricted burning of the plant can reduce the size of the plant and decrease mortality
6.Not All Barberry Is Invasive
As our extensive article about all the terrors and traumas of the Japanese barberry comes to a close, we’d like to finish off on a more positive note. Despite the invasive status of barberry plants within the U.S., there is a silver lining that is beginning to grow for those who love the way the plant looks, without risking the environment.
In recent years botanists and researchers have developed barberry varieties that are classified as less invasive, or sterile. Such varieties that you can look for are the Crimson Cutie and the Concorde Barberry.
The Crimson Cutie is a sterile variety, while the Concorde Barberry produces little to no seeds.
While the development and control methods surrounding Japanese barberry plants continue to change and grow, Plant Sentry™ encourages you to stay up to date with your regional restrictions and policies for the plant.
If you’re looking for a little help to identify whether or not the Japanese Barberry has spread to your state, be sure to visit USDA Map showing what states and areas have been affected by the spread of this plant.