Battling Japanese Knotweed

The lot my house sits on is a nice size and when we moved in a couple years ago, I had plans of doing lots of landscaping. Primarily, I wanted to plant several patches of native wildflowers on some steeper slopes and around some of the permitter. The first year, I smothered a couple sections with heavy black plastic in preparation for hand casting wildflower seeds during the following spring. The permitter of the lot had too many trees and shrubs for me to consider using more black plastic. Therefore, I started mowing and weed whacking some of this area to clear a lot of the brush; however, it wasn’t long until I realized what I was dealing with.

Quickly, and I mean really quickly, some of the brush started coming back at a rate that seemed like a foot a day. At this point, I started doing some research and learned that I was dealing with Japanese Knotweed (Fallopia Japonica). Probably one of the worse and most aggressive invasive species around. It thrives in disturbed soil, riparian areas, and along wooded lots…all of which applied in my situation. This amounted to approximately 400 feet of border, up to 20 feet deep, around my lot infected with this invasive species, not to mention a couple standalone areas.

I want to be a good steward of the planet and at least rid my property of Japanese Knotweed without the use of chemicals. So, I will tell you some of the techniques I have used to battle Japanese Knotweed. I will warn you, that this is labor of hate (love for native plants in the future though) and an effort you will have to dedicate at least 3 years, but probably more.

Japanese Knotweed has massive rhizomes that form underground and which can spread great distances at an alarming rate. These rhizomes are very strong and require a long game plan to destroy. In order to avoid using chemicals, your plan needs to be to starve this plant of energy and weaken its foundation. In order to do this, you first need to cut these giant bamboo like shoots down. This can possibly be done by trampling them with a board or tractor depending on the terrain and obstacles; however, your best option is a commerical weed whacker (or weed trimmer), such as the Echo SRM-225. You will want to combine the weed whacker with heavy duty string that is not round, but has multiple edges, such as the Echo Cross-Fire 0.095 Nylon Trimmer Line. This string is very tough, but the stalks of mature Japanese Knotweed will put up a really good fight. Your first goal is to whack all of your Japanese Knotweed down and to never let it get that big every again.

Once you have knocked all of the Japanese Knotweed down, it is suggested by some to rake up the debris and burn it. I do not fully believe this is necessary; however, it may be advised to complete the next possible step. These stalks, if left to dry, will become woody and splinter. Therefore, if you want to smother the ground with heavy black plastic, they will likely pierce the plastic. So, go ahead take the time and burn as much as you can (do not send to the dump or compost, as one small piece could potentially start a new plant).

At this point, I would advise trying different approaches to see what works best for you, but here is what I did. I had a large section of Japanese Knotweed in an open drainage area, which was perhaps 75 by 20 feet. I smothered this section with the black plastic for two seasons. This section was on the one end of my infected border and I figured I would work my way into the middle. The middle section and the other end were completely in and on the border of a wooded area. Do not kill any of the shrubs and trees in these areas! They are your friends and will help shade out Japanese Knotweed. Japanese Knotweed is so aggressive that no new plants will survive and emerge from the canopy of Japanese Knotweed, which is up to 12 feet high, without your assistance. Therefore, leave whatever else is growing and established alone, if you can.

Under your black plastic, Japanese Knotweed will keep growing and try to poke through your plastic. From time to time, you will see the plastic lifting or ballooning up, so you will need to trample it back down. You will likely get some holes here and there over time and you should try to cover them up with stones, logs, or more plastic before the Japanese Knotweed starts coming back from the brink. After two seasons, I lifted the plastic and found that most of the Japanese Knotweed had died, except around the permitter, where it will seek sunlight, and a couple places where too many holes were located and I had neglected to patch them. Regardless, what was left was a fraction of the original and greatly weakened. At this point, when you lift the plastic off you will need to quickly establish some other types of plant. I have chosen a combination of grass and native wildflower seeds.

Once your new seedlings come up, you will need to make sure they get well established. You will likely need to hand pick, weed whack, or mow sections where the Japanese Knotweed is still growing. You should do this chore once a week if you can ideally, but every two weeks will work, but do not let it go more than a month. All along, I have applied these techniques to the areas in the middle and other end section that were not smothered by black plastic. These efforts will seem fruitless, but you have to have the long road in mind. Each time you do this, you are weakening the rhizomes underneath the ground. At some point, you will notice that the rhizomes are dried up and easily broken by hand or kicking. At the least you will find them much easier to dig up and to pull the root runners out of the ground. I suggest getting a GroundHog Cultivator and a Mattock to help you dig the roots and rhizomes out of the ground.

After two and a half seasons, I still have Japanese Knotweed, but it has been greatly diminished. A couple sections have been eradicated, but most of the infected area remains; however, it is thinned out and very weakened. At this point, I tried smothering some standalone areas with free mulch and straw. I have been very pleased with the results of utilizing the free mulch. I poured it on about 6 inches deep and now even fewer shoots are popping up, but the best part now is that they are even easier to pull out because they are so leggy from working their way through the mulch. At this point, I am hoping to receive a lot more free mulch to smother the middle section, but this section is already fairly weakened due to being shaded out for the better part of spring, summer and fall.

I am fairly confident that I will have have exterminated all of the Japanese Knotweed on my property in the next year or two. The tides of war have changed. The Knotweed has been greatly weakened and now other plants are filling in and helping to accelerate the process. At this point, it is just a matter of time and dedication to mechanically removing and smothering the remaining stands of Knotweed until I win this battle. I’m hoping in three years time I will have a beautiful, established border of native wildflowers to look at.

Tools and Techniques Discussed:

  • Echo SRM-225 with Echo Cross-Fire 0.095 Nylon Trimmer Line
  • Heavy Duty Black Plastic, plus trampling down
  • Leverage existing trees and shrubs to help shade out Japanese Knotweed
  • Hand Picking
  • Mowing
  • Digging Up Rhizomes
  • GroundHog Cultivator
  • Mattock
  • Free Mulch
  • Straw

49 Comments:

  1. An interesting dialogue is worth comment. I feel that you should write extra on this matter, it might not be a taboo subject but usually individuals are not enough to speak on such topics. To the next. Cheers

  2. I really like your writing style, excellent info , thanks for posting : D.

  3. I loved as much as you will receive carried out right here. The sketch is attractive, your authored subject matter stylish. nonetheless, you command get got an shakiness over that you wish be delivering the following. unwell unquestionably come further formerly again as exactly the same nearly a lot often inside case you shield this increase.

  4. Aw, this was a really nice post. In thought I want to put in writing like this additionally – taking time and actual effort to make a very good article… but what can I say… I procrastinate alot and by no means seem to get something done.

  5. What’s up Dear, are you truly visiting this web site daily,
    if so afterward you will absolutely get pleasant experience.

  6. Everything is very open with a precise description of the issues.
    It was really informative. Your site is very helpful. Thanks for
    sharing!

  7. Hi to every one, the contents existing at this web site are actually awesome for people experience, well, keep up the nice work fellows.

  8. This article was a delightful enjoy reading. Your passion is clearly visible!

  9. You have a gift for explaining things in an understandable way. Thank you!

  10. You have a unique perspective that I find incredibly valuable. Thank you for sharing.

  11. Your ability to distill complex concepts into enjoy readingable content is admirable.

  12. Your ability to distill complex concepts into enjoy readingable content is admirable.

  13. You’ve done a fantastic job of breaking down this topic. Thanks for the clarity!

  14. I’m in awe of the way you handle topics with both grace and authority.

  15. A masterpiece of writing—you’ve covered all bases with such finesse, I’m left wanting an encore.

  16. Articulated points with finesse, like a lawyer, but without the billable hours.

  17. Thank you for the hard work you put into this post. It’s much appreciated!

  18. I’m amazed by the depth and b enjoy readingth of your knowledge. Thanks for sharing!

  19. Respect to website author, some excellent selective information.

  20. You tackled a hard to understand issue with elegance and insight. I feel much more informed after reading The post.

  21. The passion for this subject is infectious. Reading The post has inspired me to learn more.

  22. The creativity and insight left a big impression on me. Fantastic job!

  23. The approach to topics is like a master painter’s to a canvas, with each stroke adding depth and perspective.

  24. The piece was both informative and thought-provoking. Thanks for the great work!

  25. The thought-provoking post has me looking forward to more. It’s like the intellectual equivalent of a second date.

  26. The creativity and insight left a big impression on me. Fantastic job!

  27. You’ve opened my eyes to new perspectives, as if you knew the way to my curious heart.

  28. Appreciate the clarity you bring to this topic. It’s like you’re speaking to five-year-olds, which is perfect for me.

  29. The work is truly inspirational. It’s as if you’ve found a way to whisper sweet nothings to my intellect.

  30. Stumbling upon The article was a highlight of my day. It was just what I needed to read.

  31. The creativity and insight left a big impression on me. Fantastic job!

  32. The take on hard to understand topics is like a smooth ride in a luxury car—comfortable, yet exhilarating.

  33. This Writing is a treasure trove of knowledge. Thank you for The contributions!

  34. The insights add so much value, like an unexpected compliment that brightens one’s day. Thanks for sharing.

  35. You’ve articulated The points with such finesse. Truly a pleasure to read.

  36. The work is truly inspirational. It’s as if you’ve found a way to whisper sweet nothings to my intellect.

  37. Thanks for a marvelous posting! I definitely enjoyed reading it, you happen to be a great author.I will remember to bookmark your blog and will eventually come
    back sometime soon. I want to encourage you to ultimately continue your great work,
    have a nice weekend!

  38. The perspective is incredibly valuable to me. Thanks for opening my eyes to new ideas.

  39. Thoroughly insightful read, or so I thought until I realized it was The expertise shining through. Thanks for making me feel like a novice again!

  40. What i don’t understood is in reality how you are not actually a lot
    more neatly-liked than you may be right now. You’re very intelligent.
    You know therefore significantly in terms of this matter, produced me for my
    part believe it from so many numerous angles. Its like women and
    men aren’t interested except it is one thing to do with Girl gaga!

    Your individual stuffs outstanding. All the time maintain it up!

  41. The article was a delightful read, and The passion shines as brightly as The intellect. Quite the combination!

  42. The words are like seeds, planting ideas that blossom into understanding and appreciation.

  43. Hello, I read your new stuff regularly. Your writing style is
    witty, keep up the good work!

  44. This post has been incredibly helpful to me. The guidance is something I’m truly grateful for.

  45. Hi there, I found your blog by way of Google while searching for a similar subject, your
    site got here up, it seems to be great. I have bookmarked it in my google bookmarks.

    Hi there, just become alert to your weblog through Google,
    and found that it is truly informative. I am going
    to be careful for brussels. I’ll be grateful in the event you proceed this in future.

    Lots of other folks will be benefited from your writing.
    Cheers!

  46. I’m officially a fan of The work. It’s like having a crush, but intellectually stimulating.

  47. The way you articulate The thoughts is as refreshing as the first sip of coffee in the morning.

  48. Thank you for shedding light on this subject. The perspective is refreshing!

  49. Opened my eyes to new perspectives, and here I was thinking I’d seen it all.

Leave a Reply

Your email address will not be published. Required fields are marked *