Japanese Barberry



Japanese Barberry (Berberis thunbergii) is one tough plant. It is drought, shade and deer-resistant and spreads by seed, by root and by dropping a branch over the ground where it then grows roots and forms a daughter plant. It's been widely planted as an ornamental throughout the United States and has easily escaped cultivation, forming dense thickets throughout pastures and forests, particularly in the northeast. Japanese Barberry has been listed as an invasive species and banned in over 20 states so far, most recently, in New York State.

Japanese barberry stems in a roadside thicket by Eve Fox, the Garden of Eating, copyright 2014
This thorny shrub with little red berries poses a number of very big problems:

It proliferates very quickly, creating impenetrable stands and thickets wherever it grows and crowding out native vegetation that provides ideal sustenance and habitat for native animal life. Because deer will not eat it, it has a huge advantage over native plants. It's so aggressive that it has earned a well-deserved place on the National Parks Service's Plant Conservation Alliance's "Least Wanted" list.


Japanese barberry also alters the soil pH and nitrogen levels in a way that is damaging to the ecosystem. These changes attract earthworms which, shockingly, are also not native to the U.S.. The worms in turn eat the leaf litter of the forest floor, leaving soil exposed which increases erosion and runoff, creating gullies, washing sediment into streams where it increases the likelihood of algal blooms in larger bodies of water, releasing carbon dioxide into the atmosphere and leaving the forest floor less hospitable to plant life. Here's more from NPR about this vicious cycle.

Barberry's leaves can be green, red or purpleish in color. Plants can be neatly manicured or grow in a wild tangle.
Perhaps most disturbing, Japanese barberry provides the perfect conditions for black-legged (aka "deer") ticks - the primary vector for the spread of Lyme disease and a number of other blood-borne diseases including babesiosis, ehrlichiosis and anaplasmosis. Its dense thickets provide the humidity that baby ticks require, earning it the charming nickname of "tick nursery".

Studies done by University of Connecticut and CAES (Connecticut Agricultural Experiment Station) found that forests infested with Japanese barberry contained 12 times more Lyme-disease-infected ticks than unspoiled forest -- a shocking 120 Lyme-infected ticks per acre of barberry-infested forest compared with just 10 Lyme-infected ticks in the undisturbed forest. They also found that controlling the Japanese barberry bushes in the forest cut the number of ticks by 80%.

A "questing" deer tick reaches its legs out in hopes of hopping on to its next blood meal.
Clearly, it is to our advantage to get rid of Japanese barberry in our yards, forests and landscaped plantings! But how, you ask? It’s not easy but it can be done.

CONTROLLING JAPANESE BARBERRY

 The first method is by far the easiest: DO NOT PLANT IT! You should also encourage others not to plant it - share that little tidbit about120 Lyme-infected ticks vs 10 Lyme-infected ticks if you meet with any resistance... Here in my home state of New York, it's recently been banned but nurseries have another year to sell down their stock - it can't hurt to ask nursery owners to dispose of the plants - worst they can say is "no".


Any barberry plants that are growing need to go. Unfortunately, it's a very tenacious plant. There are a few different methods and you will probably have to use more than one method in combination over a year (or more) to truly kill each plant.

1. MANUAL

 You can remove the bushes by pulling them out by hand which is really only possible with young plants up to three feet high. You will probably want to start by cutting them back using a pair of long-handled snips or shears (I love these loppers by Fiskars) to remove the spiny branches and allow you to get to the base of the plant and its roots. Small plants often come up pretty easily but be sure to wear thick gloves (leather gloves marketed as "rose gloves" are most effective) and thick, protective clothing and to check thoroughly for ticks afterwards. You may also have success using a tool like a root remover to yank them out. People apparently loved the Weed Wrench but they seem to have gone out of business.

It's very important to get as many of the roots out as you can as the plant will simply resprout from any roots left in the ground. If the plants you’re pulling up have berries on them, it is best to dispose of them by burning them to avoid reseeding wherever you drop them. You can also bag them but they're just so large that bagging seems unrealistic. If you do burn the plants, be sure to follow all burning regulations for your area.

Japanese barberry berries in late fall by AnneHeathen via Flickr
2. MECHANICAL

 You can mow down a lot of barberry fairly chickly using a gas-powered trimmer with a brush blade attachment. This is what we plan to do for the areas of our woods where the barberries have grown into a truly dense tangle. Again, you may wish to hire someone to do this for you.


If you're dealing with a large area and well-established plants, you may wish to hire someone to come through with a skid steer equipped with a brush mowing attachement - this makes the most sense for an overgrown meadow or forest situation.

Photo courtesy of Pennsylvania Dept of Conservation and Natural Resources
If you have well-established plants in your yard or garden, hiring someone with a mini-backhoe is probably the best choice - just be strategic about how you get the machine in and out to avoid destroying your lawn.

3. CHEMICAL

 You can kill barberry by applying an herbicide like Roundup (glyphosate) either to the leaves using a mister or directly to the stems of a plant you've hand cut or mowed. However, using an herbicide is my least favorite approach because you will also be adding toxic poisons to the soil and water in your yard or woods. I have not personally gone this route and do not recommend it but do feel you should know about it as an option.

Applying an herbicide to the characteristically bright yellow stems of a mowed barberry bush. Photo courtesy of Pennsylvania Dept of Conservation and Natural Resources
4. FIRE

 Japanese barberry is NOT adapated to fire so burning it is an effective method of control. Proper, safe application of a propane torch after a good hard rain 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 local burn restrictions. This is another method you might want to hire someone with experience to handle. CAES has several very useful video tutorials which you can find in the resources section below if you're interested in pursuing this method.

After doing some research, I bought this 400,000 BTU propane torch last year - the squeeze valve is kind of important to have, methinks. Again, don't go this route without being thoroughly educated and prepared first! Follow your local burning regulations, only use the torch after a heavy rain when there is no wind, make sure you have a good supply of water on hand, and put out all embers before moving on. You. Do. NOT. Want. To. Start. A. Forest. Fire.

Jeff Ward, chief scientist in the department of forestry and horticulture at the Connecticut Agricultural Experiment Station demonstrates the use of a propane torch. (Photo courtesy of CAES)
TIMING

 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. Burn or bag any branches that have seeds.

PREVENTING THEIR RETURN

 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 they (or something else invasive) will move in and you’ll be right back where you started. But be mindful of the fact that anything that is not deer-resistant will get eaten unless it's in a deer-fenced area or you fence the new plantings. We are trying out planting a handful of willow switches in a swampy area of our woods that has a lot of barberry. And we're covering them with these Tubex tree tubes to prevent the deer from munching them at the advice of Ethan and Dyami of Appleseed Permaculture.

What you plant will depend on the soil, drainage and sunlight in the area you’re dealing with but I've listed a few native shrubs, bushes and groundcovers below. Check with a native plant nursery or specialist in your area for recommendations that are tailored to your region. In my neck of the woods, Catskill Native Nursery is a great source for advice and plants.
  • Low or high bush blueberries which grow naturally in the acidic soil and dappled light of pine forests Sweetfern (also likes pine forest and roadsides)
  • New Jersey tea
  • Creeping sumac (pretty fall foliage)
  • Dwarf witchalder 
  • Virginia sweetspire
  • Willows (they love water)
  • Allegheny pachysandra (groundcover)
  • Wild ginger (groundcover)
  • Foam flower (groundcover)
  • Phlox pilota (groundcover)
  • Subulata (groundcover)
  • Various ferns (groundcover)
RESOURCES

You can find more information about tackling this thorny problem at the links below:
You might also like:
For delicious recipes, gardening ideas, foraging tips, and food-related inspiration "like" the Garden of Eating on Facebook, or follow me on Twitter and Pinterest.

3 comments:

Anonymous said...

Really?? And they already destroyed Japan? Ethworm destroying forests? A bush not eaten by deers is infested from deer ticks. But the solution is glyphosate...a radioactive mineral who disrupts the kreb circle of plants, insects, animals.





December 14, 2018 at 5:51 AM
Eve Fox said...

Hi Anonymous,
I was merely sharing the information that is out there from reputable scientific authorities - if you actually read my article you'd notice that the reason these plants are tick nurseries has little to do with deer and a lot to do with the white footed mouse - one of the primary hosts for the ticks that transmit Lyme disease. As for the glyphosate, I have personally never used it as I think it's the devil incarnate but wanted to share all the ways people can tackle this plant. I have spent considerable time pulling, cutting and burning this plant that's taken over our woods. If you'd read the article in any detail, you would have noticed this sentence: "However, using an herbicide is my least favorite approach because you will also be adding toxic poisons to the soil and water in your yard or woods. I have not personally gone this route and do not recommend it but do feel you should know about it as an option."

I never implied that this plant or the earthworms have destroyed Japan -- the reason for that is that there are other plants and insects in Japan that keep them in balance there. That is why they are considered INVASIVE here.

I'll close by saying that your comment was both ill-informed and unnecessarily nasty. Why don't you save your sarcasm for the company that makes Roundup? Go send 'em an angry letter instead of ruining my morning. And if you're going to leave snide comments - have the courage to use your name at least. Best, Eve

December 14, 2018 at 8:26 AM
Unknown said...

Great article. It looks like you put a lot of work into it. As for the anon hate about using glyphosate, as someone who has worked in conservation it's not the end of the world to use small amounts carefully applied to particular plants as a means to control an invasive. Invasive species or more harmful to an ecosystem than the chemical when properly applied especially since it tends to break down in the soil within a week or two. If I do use it though I buy if from a company not owned by Monsanto of course. Thanks for putting so much effort into creating well structured easily accessible information like this.

May 16, 2021 at 2:33 AM

Post a Comment

Japanese Barberry



Japanese Barberry (Berberis thunbergii) is one tough plant. It is drought, shade and deer-resistant and spreads by seed, by root and by dropping a branch over the ground where it then grows roots and forms a daughter plant. It's been widely planted as an ornamental throughout the United States and has easily escaped cultivation, forming dense thickets throughout pastures and forests, particularly in the northeast. Japanese Barberry has been listed as an invasive species and banned in over 20 states so far, most recently, in New York State.

Japanese barberry stems in a roadside thicket by Eve Fox, the Garden of Eating, copyright 2014
This thorny shrub with little red berries poses a number of very big problems:

It proliferates very quickly, creating impenetrable stands and thickets wherever it grows and crowding out native vegetation that provides ideal sustenance and habitat for native animal life. Because deer will not eat it, it has a huge advantage over native plants. It's so aggressive that it has earned a well-deserved place on the National Parks Service's Plant Conservation Alliance's "Least Wanted" list.


Japanese barberry also alters the soil pH and nitrogen levels in a way that is damaging to the ecosystem. These changes attract earthworms which, shockingly, are also not native to the U.S.. The worms in turn eat the leaf litter of the forest floor, leaving soil exposed which increases erosion and runoff, creating gullies, washing sediment into streams where it increases the likelihood of algal blooms in larger bodies of water, releasing carbon dioxide into the atmosphere and leaving the forest floor less hospitable to plant life. Here's more from NPR about this vicious cycle.

Barberry's leaves can be green, red or purpleish in color. Plants can be neatly manicured or grow in a wild tangle.
Perhaps most disturbing, Japanese barberry provides the perfect conditions for black-legged (aka "deer") ticks - the primary vector for the spread of Lyme disease and a number of other blood-borne diseases including babesiosis, ehrlichiosis and anaplasmosis. Its dense thickets provide the humidity that baby ticks require, earning it the charming nickname of "tick nursery".

Studies done by University of Connecticut and CAES (Connecticut Agricultural Experiment Station) found that forests infested with Japanese barberry contained 12 times more Lyme-disease-infected ticks than unspoiled forest -- a shocking 120 Lyme-infected ticks per acre of barberry-infested forest compared with just 10 Lyme-infected ticks in the undisturbed forest. They also found that controlling the Japanese barberry bushes in the forest cut the number of ticks by 80%.

A "questing" deer tick reaches its legs out in hopes of hopping on to its next blood meal.
Clearly, it is to our advantage to get rid of Japanese barberry in our yards, forests and landscaped plantings! But how, you ask? It’s not easy but it can be done.

CONTROLLING JAPANESE BARBERRY

 The first method is by far the easiest: DO NOT PLANT IT! You should also encourage others not to plant it - share that little tidbit about120 Lyme-infected ticks vs 10 Lyme-infected ticks if you meet with any resistance... Here in my home state of New York, it's recently been banned but nurseries have another year to sell down their stock - it can't hurt to ask nursery owners to dispose of the plants - worst they can say is "no".


Any barberry plants that are growing need to go. Unfortunately, it's a very tenacious plant. There are a few different methods and you will probably have to use more than one method in combination over a year (or more) to truly kill each plant.

1. MANUAL

 You can remove the bushes by pulling them out by hand which is really only possible with young plants up to three feet high. You will probably want to start by cutting them back using a pair of long-handled snips or shears (I love these loppers by Fiskars) to remove the spiny branches and allow you to get to the base of the plant and its roots. Small plants often come up pretty easily but be sure to wear thick gloves (leather gloves marketed as "rose gloves" are most effective) and thick, protective clothing and to check thoroughly for ticks afterwards. You may also have success using a tool like a root remover to yank them out. People apparently loved the Weed Wrench but they seem to have gone out of business.

It's very important to get as many of the roots out as you can as the plant will simply resprout from any roots left in the ground. If the plants you’re pulling up have berries on them, it is best to dispose of them by burning them to avoid reseeding wherever you drop them. You can also bag them but they're just so large that bagging seems unrealistic. If you do burn the plants, be sure to follow all burning regulations for your area.

Japanese barberry berries in late fall by AnneHeathen via Flickr
2. MECHANICAL

 You can mow down a lot of barberry fairly chickly using a gas-powered trimmer with a brush blade attachment. This is what we plan to do for the areas of our woods where the barberries have grown into a truly dense tangle. Again, you may wish to hire someone to do this for you.


If you're dealing with a large area and well-established plants, you may wish to hire someone to come through with a skid steer equipped with a brush mowing attachement - this makes the most sense for an overgrown meadow or forest situation.

Photo courtesy of Pennsylvania Dept of Conservation and Natural Resources
If you have well-established plants in your yard or garden, hiring someone with a mini-backhoe is probably the best choice - just be strategic about how you get the machine in and out to avoid destroying your lawn.

3. CHEMICAL

 You can kill barberry by applying an herbicide like Roundup (glyphosate) either to the leaves using a mister or directly to the stems of a plant you've hand cut or mowed. However, using an herbicide is my least favorite approach because you will also be adding toxic poisons to the soil and water in your yard or woods. I have not personally gone this route and do not recommend it but do feel you should know about it as an option.

Applying an herbicide to the characteristically bright yellow stems of a mowed barberry bush. Photo courtesy of Pennsylvania Dept of Conservation and Natural Resources
4. FIRE

 Japanese barberry is NOT adapated to fire so burning it is an effective method of control. Proper, safe application of a propane torch after a good hard rain 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 local burn restrictions. This is another method you might want to hire someone with experience to handle. CAES has several very useful video tutorials which you can find in the resources section below if you're interested in pursuing this method.

After doing some research, I bought this 400,000 BTU propane torch last year - the squeeze valve is kind of important to have, methinks. Again, don't go this route without being thoroughly educated and prepared first! Follow your local burning regulations, only use the torch after a heavy rain when there is no wind, make sure you have a good supply of water on hand, and put out all embers before moving on. You. Do. NOT. Want. To. Start. A. Forest. Fire.

Jeff Ward, chief scientist in the department of forestry and horticulture at the Connecticut Agricultural Experiment Station demonstrates the use of a propane torch. (Photo courtesy of CAES)
TIMING

 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. Burn or bag any branches that have seeds.

PREVENTING THEIR RETURN

 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 they (or something else invasive) will move in and you’ll be right back where you started. But be mindful of the fact that anything that is not deer-resistant will get eaten unless it's in a deer-fenced area or you fence the new plantings. We are trying out planting a handful of willow switches in a swampy area of our woods that has a lot of barberry. And we're covering them with these Tubex tree tubes to prevent the deer from munching them at the advice of Ethan and Dyami of Appleseed Permaculture.

What you plant will depend on the soil, drainage and sunlight in the area you’re dealing with but I've listed a few native shrubs, bushes and groundcovers below. Check with a native plant nursery or specialist in your area for recommendations that are tailored to your region. In my neck of the woods, Catskill Native Nursery is a great source for advice and plants.
  • Low or high bush blueberries which grow naturally in the acidic soil and dappled light of pine forests Sweetfern (also likes pine forest and roadsides)
  • New Jersey tea
  • Creeping sumac (pretty fall foliage)
  • Dwarf witchalder 
  • Virginia sweetspire
  • Willows (they love water)
  • Allegheny pachysandra (groundcover)
  • Wild ginger (groundcover)
  • Foam flower (groundcover)
  • Phlox pilota (groundcover)
  • Subulata (groundcover)
  • Various ferns (groundcover)
RESOURCES

You can find more information about tackling this thorny problem at the links below:
You might also like:
For delicious recipes, gardening ideas, foraging tips, and food-related inspiration "like" the Garden of Eating on Facebook, or follow me on Twitter and Pinterest.

3 comments:

Anonymous said...

Really?? And they already destroyed Japan? Ethworm destroying forests? A bush not eaten by deers is infested from deer ticks. But the solution is glyphosate...a radioactive mineral who disrupts the kreb circle of plants, insects, animals.





December 14, 2018 at 5:51 AM
Eve Fox said...

Hi Anonymous,
I was merely sharing the information that is out there from reputable scientific authorities - if you actually read my article you'd notice that the reason these plants are tick nurseries has little to do with deer and a lot to do with the white footed mouse - one of the primary hosts for the ticks that transmit Lyme disease. As for the glyphosate, I have personally never used it as I think it's the devil incarnate but wanted to share all the ways people can tackle this plant. I have spent considerable time pulling, cutting and burning this plant that's taken over our woods. If you'd read the article in any detail, you would have noticed this sentence: "However, using an herbicide is my least favorite approach because you will also be adding toxic poisons to the soil and water in your yard or woods. I have not personally gone this route and do not recommend it but do feel you should know about it as an option."

I never implied that this plant or the earthworms have destroyed Japan -- the reason for that is that there are other plants and insects in Japan that keep them in balance there. That is why they are considered INVASIVE here.

I'll close by saying that your comment was both ill-informed and unnecessarily nasty. Why don't you save your sarcasm for the company that makes Roundup? Go send 'em an angry letter instead of ruining my morning. And if you're going to leave snide comments - have the courage to use your name at least. Best, Eve

December 14, 2018 at 8:26 AM
Unknown said...

Great article. It looks like you put a lot of work into it. As for the anon hate about using glyphosate, as someone who has worked in conservation it's not the end of the world to use small amounts carefully applied to particular plants as a means to control an invasive. Invasive species or more harmful to an ecosystem than the chemical when properly applied especially since it tends to break down in the soil within a week or two. If I do use it though I buy if from a company not owned by Monsanto of course. Thanks for putting so much effort into creating well structured easily accessible information like this.

May 16, 2021 at 2:33 AM

Post a Comment