And any advice how to get rid of it from my back yard :) It comes back bigger and stronger every year. Location: Toronto, ON. Many thanks!
Japanese Knotweed... Maybe you could eat it? http://www.eattheweeds.com/japanese-knotweed-dreadable-edible/ I'm not sure there's any good ways to eradicate.... Japanese Knotweed out-lives the gardener and the garden.
We have been performing stem injections on knotweed throughout the lower mainland. That will get rid of it
nicotiana rustica has been used by south american peoples as a weed and bug killer for thousands of years. after visiting and seeing the multiple uses i tried to get some seeds or plants here and could not find them, so i purchased some seeds down in Costa Rica on my next visit. i have been growing the seeds locally for over 20 years. i have tons and could send you some. the originals came from an ancient seed stash found to be over 1000 years old, ( i believe they can be bought on line from salt spring island seeds @ www.saltspringseeds.com for out of country sales) or so i was told. we use it on the moss which grows on almost every roof, (pulling it off can damage cedar shingles) ants, dock, blackberry, dandelions, thistle and many other weeds. it is a natural weed killer that has beautiful yellow flowers that smell sweetly, the plant is pleasing to the eye and will live well no matter the climate. 3 plants will produce enough concentrate to keep the yard clean and free of weeds. used at full strength on cracks in side walk, driveway or stairs and never see another weed there again. its amazing. depending on the heat in your zone, depends on how fast the sun will kill it. cut plant at base to expose roots, put 1 oz of pure concentrate for hard to kill weeds and wait 10 days until its completely dry and gone. water and correct ph of soil if necessary. if you can not wait until seeds arrive and grow, two 50 gm pouches of natural tobacco (without chemicals) boiled in water on stove over low heat, (just enough water to cover tobacco) for 15 mins, stir,(smells bad) let stand over night. strain. heat again, boil down to dark red/brown, no longer cloudy, and its ready too use. i use 2 oz mix to 8-10 oz water, my sister inlaw uses 2 oz to the litre, but we all use it full strength on the nasty weeds, like dock and blackberry, morning glory and ants. good luck. personal message me and i will send you some seeds. peace.
It likes where it is living, so change that. Try using vinegar and salt to shock it if you want a non-chemical solution. Nicotinic acid is great but hardly Earth friendly. Using tobacco products is a detriment to the watershed ecosystem (it should only be painted on the leaves or cut stem). I'm leading toward increasing the acidity of the soil.
Those are both chemicals! Neither is salt. Vinegar and salt are also detrimental to watershed ecosystems. Direct stem injections of systemic herbicide as suggested by Ryan K are far more effective in killing the weed with minimal side effects toward other plants nearby.
I agree 100% on the salt, but please do explain how weak acids such as Vinegar are harmful? I use them all the time to neutralize my pH 10 water and 8+ pH soil. Seems extraordinarily beneficial to me.
In Michigan we use salt a lot during winter months so i am not sure i would worry about a half cup of salt. In a gallon of vinegar to kill weeds. Much better option to spraying so called organic pesticides, which are only organic due to their plant background...not at all EEarth friendly. We see lots of problems in local lakes with pesticide use. Vinegar nutralizes in soil to make a salt. Also I am sorry about confusing vinegar and salt as non chemicals...also, i probably should have mentioned dyhydrogen monoxide...not there is a chemical for you. Pretty dangerous stuff :)
The problem with salts is they frequently accumulate in soil to the point that the soil is toxic to most plants and other organisms. No point in killing off a noxious weed if you cant grow anything else in it's place! http://www.lakesuperiorstreams.org/understanding/impact_salt_2.html
yes, using the nicotiana rustica or any tobacco plant IS drastic measures, i don't recommend using it without gloves , long sleeve shirt and pants in case of contact. ( would be like smoking 35 packs of organic cigarettes!) nicotine poisoning is possible from direct contact with spray. yet when all other avenues have failed to work, this plant spray works extremely well. contact with plant has no danger, just the boiled concentrate. we only use it when all else fails, or on plants that have a history of spreading underground and multiplying no matter what we do...after a good rain, or soak with the hose, the grass moves in where the weeds once were, strawberries are growing in the area where i once grew the plant, and where weeds were just treated this spring.
No doubt that it works. Teaspoon full ingested by human is highly toxic, if not deadly. So gloves are wise as is a dedicated pot. But it will definitely work!
Sudden changes in water pH are lethal to a lot of aquatic fauna. Granted a cupful wouldn't hurt, but that wouldn't harm the knotweed either. Enough to kill the knotweed would be damaging, though. Yes, dihydrogen monoxide (DHMO) can be very damaging, too, I've seen everything from pot plants to extensive areas of large trees killed by DHMO, while additionally many plants are extremely sensitive to solid forms of DHMO, particularly if applied during active growth. ;-)
Well the Vinegar is fully buffered by the time (if ever) it were to reach a waterway. But I promise not to pour it directly into a stream ;-)
I just spent weeks clearing all the stalks and roots I could possibly get at in the new home I purchased. A friend cleared a bunch of the dry ones in autumn when we first moved in, but we have a half acre, so there was plenty more, and I just got the last one 2 days ago. I pop off new heads every time I go out there and try to dig up the roots that are starting them if I can. We don't want to use chemicals, so the advice I've been following is: Dig them up. Then dig them up again. And again. I've been told it'll take years, but I feel like I just won the last big battle, and now just need to hold taken ground.
And again until the end of time. Try planting shrubs that prevent other things from growing..,once established. Evergreens like spruce, arbs, eunoms, boxwood...or the best weed prevention i have ever seen, a black oak.