Getting rid of knotweed without round-up?
Hi all, We are about to take on our totally neglected backyard, and we have a big patch of Japanese knotweed. Has anyone hired anyone who was able to get rid of (or at least reduce the presence of) knotweed without using round-up or other herbicides? We have little kids and would rather stay away from the chemicals. Thanks for your advice! Suzy
suzy
in Landscaping 10 years ago
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15 replies
donnawalrond | 9 years and 4 months ago
There are some non-chemical methods to control Japanese Knotweed: When tackling Japanese knotweed, cultural control methods pose some problems; Digging out is possible, but due to the depth that the rhizomes can penetrate, regrowth usually occurs. This method also creates problems over disposal as Japanese knotweed is classed as ‘controlled waste’ under the Environmental Protection Act 1990\. This requires disposal at licensed landfill sites. Specialist Japanese knotweed contractors are usually licensed to safely remove the weed from site but check first before employing their services. Alternatively, it can be destroyed on site by allowing it to dry out before burning. On no account should Japanese knotweed be included with normal household waste or put out in green waste collection schemes If digging out is attempted, remove as much root as possible, then repeatedly destroy regrowth. In this way the energy reserves in the remaining underground parts will be gradually exhausted; a process which may, however, take several seasons Biological control A plant sucker (psyllid) is being released in the UK as a biological control for Japanese knotweed. It is currently only being released at a handful of trial sites and is not available to gardeners. However, if successful it will be released more widely and will become widespread in Britain over the next five to ten years by natural spread. Although, you can do this on your own but if you find difficulty in doing this. I advice you to contact professionals like landscaping firm.
suzy | 10 years ago
Thanks so much for all of your answers– this is really helpful information. It sounds like we’re lucky on two counts: 1) past owners put concrete over almost the whole yard, which we hate, but it means the knotweed is only in the back quarter and 2) our yard is the neglected one in our little stretch of houses, so if we get rid of the knotweed, I don’t think it’s growing anywhere else around us. Silver lining, I guess?
chjuran | 10 years ago
we dealt with this for several years, after redoing our neglected yard. As others have said, it is just vigilance, virtually on a daily basis. (This stuff is really fast growing.) Gently pluck out the shoots, and throw them in the trash. Don’t compost them, the tuberous roots will generate new shoots. See if there is any growing in neighboring yards and maybe your see if your you can get your neighbors to take action to eliminate it as well. Once we had established other garden plants, the problem lessened, and the lawn seems to do particularly well to suppress new growth. There is still the random opportunistic shoot now and then but the labor to suppress will pay off. It’s very exasperating, but don’t give up!
Guest User | 10 years ago
I didn’t mention anything about the price, no-permits. That’s up to the homeowner to look into if they choose, though I’m sure your estimate is appreciated. And I think everyone’s comments have made it quite clear that knotweed is intrepid.
slopefarm | 10 years ago
My $.02 on bindweed. 1\. Don’t let it go to flower. You don’t want it re-seeding itself. 2\. Pull gently at the root to try to pull as much root out with each stalk as you can. 3\. It will keep growing back, but if you keep pulling as much root as you can, each year it will be less intense. Took 3-4 summers, but now I rarely see it.
no-permits | 10 years ago
redrobin, removing 90+ yards of dirt from an average sized backyard (20×60), then trucking 90 yards in is easily a $20k job and 15 dumpsters. there is still no guarantee you will get all the roots either.
Guest User | 10 years ago
That’s a great idea, Suzy. Had my husband and I known what we were in for, we would have had someone do all the work. The other thing you should think about is the quality of your soil. If you decide to go the DIY route, get your soil tested to see the lead content, etc. Ours was off the charts and in our digging we found what we think is the residue from burning coal about 6-12 inches down in a number of locations. Needless to say, we aren’t growing anything edible in the soil. For your situation, with children, you don’t want them playing in the yard if the quality of the soil is bad. This may be yet another reason to get rid of the top couple of feet. Brooklyn College does soil testing: http://www.brooklyn.cuny.edu/web/academics/centers/esac/services/soil.php. You have to send in samples and then wait for the results.
suzy | 10 years ago
Redrobin, that sounds really hard. We’re doing a whole concrete removal/ retaining wall replacement project this summer, so it sounds like it might be worth tacking on the digging up of the non-concrete portion of the yard while we’re at it.
daveinbedstuy | 10 years ago
Just as an aside, which won’t be appreciated by anyone with knotweed problems, I once saw Bobby Flay grill the tender spring shoots.
sethamin | 10 years ago
We’re in the midst of a 2 year ongoing battle with knotweed in our backyard. We covered it with heavy plastic for months to “burn” it out, which mostly worked but still left some of it alive. At this point we’re reduced to being vigilant and pulling up shoots as we spot them. I really hope this is the last year we’ll have to do this, but it is amazingly resilient.
Guest User | 10 years ago
The roots can go down as deep as 3-4 feet. And if the knotweed has been there for a long time, they can be over 1 inch in diameter. My husband and I dug it out systematically, about a 2 ft section at a time, but then we sifted through all the dirt to remove any remaining roots. A 1-inch piece of root will regrow! Because it was in our neighbors yards as well, we put metal sheeting along the fence line to help prevent the roots from their yards coming back into ours. After digging everything up, we put the dirt back in and covered the dirt with landscape fabric — the good heavy-duty kind. This was back-breaking work that we did over the course of two summers and for which I ended up in physical therapy for my shoulder. If the knotweed is throughout the yard and you can afford it, hire someone to dig out and dispose of at least 2 feet of dirt, then put down the landscape fabric and put new dirt down. One thing that is critical, no matter your approach, is that you never let the knotweed flower in the fall as that will spread the seeds. There’s loads of information on this nasty invasive weed if you Google it. The good news is we were successful.
suzy | 10 years ago
Thanks, guys! I had this idea that we would have to, like, excavate the entire yard, but this sounds more like something I can do myself.
littleyellowhouse | 10 years ago
I did this by cutting all the knotweed down and digging up all the roots I could get at, and then systematically pulling out the shoots that came up every week. I figured that if the shoots never had access to sunlight, sooner or later the plant would have to die. I pulled shoots every week for about two years, and then the evil knotweed was gone.
daveinbedstuy | 10 years ago
You have to get all the roots out. It’ll be an ongoing process. You will have thought you got them and then new shoots will appear. It can eventually be done.
no-permits | 10 years ago
i’d just hack it down, dig up the roots and put down some of that black weed barrier then put whatever you want (dirt, gravel, soil, mulch) on top of that. it’s definitely a DIY project unless you are crippled or something.