Japanese barberry. Whether or not you know its name, you’ve probably seen it before. After all, it’s one of the most widely used ornamental plants in the U.S. If you have a yard, there’s a good chance you’ve got one or more planted in it. If not, you’ve probably seen it planted as a neatly trimmed shrub outside your bank or just growing in a wild tangle at the side of the road.
Which is a BIG problem because:
1. Japanese barberry is crowding out native plants all along the eastern U.S. It’s considered so aggressive that it’s on the Plant Conservation Alliance’s “Least Wanted” list;
2. The plants alter soil pH, nitrogen levels, and biological activity in a way that attracts earthworms which, surprisingly, are not native to North America and, also surprisingly, are damaging forest ecosystems. The worms eat up the leaf litter on the forest floor, resulting in gullies, washing sediments into streams, increasing the likelihood of algae blooms, and releasing carbon dioxide into the atmosphere; and last but definitely not least,
3. Japanese barberry bushes provide the perfect conditions for deer (a.k.a. black legged) ticks, the primary vector for Lyme disease, a dreaded, difficult to diagnose and even harder to treat tick-borne illness that is sweeping the nation.
Recent studies done by the University of Connecticut and the Connecticut Agriculture and Experiment Station (CAES) found that forests infested with Japanese barberry had 12 times more deer ticks than forests that were not - 120 disease-infected ticks per acre compared with just 10 infected ticks per acre of unspoiled forest. That’s pretty darn significant!
The good news is that they also found that controlling Japanese barberry can cut tick populations by up to 80% which can go a long ways to reducing the number of people who develop the red bullseye rash and flu-like symptoms of Lyme disease.
CONTROLLING JAPANESE BARBERRY
So how do you stop a plant that is the botanical equivalent of The Terminator? It’s not easy but it can be done.
1. The first method is by far the easiest: DO NOT PLANT IT! You can also encourage others not to plant it or sell it. Just bust out that fact about the 120 Lyme disease-infected ticks vs. 10 Lyme disease-infected ticks — it will probably do the trick.
2. But once they’re growing, you have to kill them. It’s hard to do – this is a pretty tenacious plant. You can remove the bushes by pulling them out by hand which is really only possible with young plants up to three feet high. They usually come up pretty easily but be sure to wear thick gloves and protective clothing and to check thoroughly for ticks afterwards. You may also have success using a tool like a Puller Bear to yank them out. If the plants you’re pulling up have berries on them, it is best to dispose of them by burning them.
You can also cut them back using long-handled shears or snips (this is kind of frustrating and thorny, though). You will be able to power through a lot more barberry using a gas-powered brush wacker.
Or, if you have access to heavy machinery, you can also accomplish a lot quickly using a mini-backhoe but that requires hiring someone who knows what they’re doing and may also be rather hard on your lawn or your woods.
3. No matter how ruthlessly you cut them back, they will grow back again so you’ve gotta be prepared to beat them back when they attempt to make a repeat appearance. It seems that the most effective way to do this is to follow up with either a chemical like Roundup or with FIRE. I’m not a big fan of Roundup and its ilk so I would not recommend that method. But proper, safe application of a propane torch can be very useful in making sure barberry gets the message that it is not wanted though it is something one should only try with proper training and while following both safety instructions and also local burn restrictions. Try to pull plants in early spring and mow, cut or torch them in late summer to ensure that they’re not able to spread their seeds.
4. Last but not least, you must plant something native in place of the Japanese barberry bushes you’ve removed. If you don’t, there’s a good chance that something else invasive will move in and you’ll be right back where you started.
What you plant will depend on the soil, drainage and sunlight in the area you’re dealing with but some native shrubs and bushes that may work are low or high bush blueberries which grow naturally in the acidic soil and dappled light of pine forests, New Jersey tea, creeping sumac, dwarf witchalder and Virginia sweetspire. Or consider Allegheny pachysandra, wild ginger, foam flower, phlox pilota or subulata or ferns for beautiful, native ground covers.
You can find more information about tackling this thorny problem at the links below:
- Plant Conservation Alliance’s Alien Plants Working Group Fact Sheet on Japanese Barberry
- Three-part video series about Japanese Barberry, its role in the forest, how to control it and its relationship to Lyme disease:
- UCONN Today article about the research being done around controlling barberry in forests and Lyme disease
- State of Connecticut’s Reference Guide for Foresters and Woodland Managers on Methods of Controlling Barberry
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- Garden Reclamation – Trying to Outcompete Invasives
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