Herbicide (weed/grass killer) Basic Information

[rswyan]

Trimec is not 2,4D. It contains 2,4D as one of the 3 chemicals in it's make up. It also does NOT control crabgrass which is NOT a broadleafed weed.

But Trimec Plus supposedly does ..... (never used it myself)

 

[James150]

Japanese Knotweed . . . .Nasty stuff. Cut the stems and inject or paint them with roundup while they are fresh.

This stuff travels underground by runners up to 40'. I've seen it come up through asphalt or packed down gravel.

We had a stand 40' X 60' and ten feet high when we bought our land ten years ago. I cut it, I burned it, I poisoned it and except for a few shoots I'm always cutting with the mower that come from the cornfield next door, I'm knotweed free.

I have no illusions that if I stopped cutting and poisoning it would be back in full force in a year or two.

BTW, it also propogates from small pieces, so if you cut it, and part of a plant is washed down into the ditch, it will take hold and wreak havoc. Nasty stuff.

Jim (BTW, I'm in ag zone 4 in SW WI)

 

[johnk]

I am going to try the Roundup route after the garden quits producing in a week or so. I was planning on cutting the whole garden down, spraying, waiting a few days, rototilling and spraying again. Ur should I not rototill and selectively spray the Knotweed?

 

[clemsonfor]

Spraying the whole garden depends on weather you want to spend the money to do that size area, it will not hurt as you will kill all the weeds and grasses. I would also spray it weather you spot spray or do the whole area and let it sit at least a week if not 1.5 weeks to make sure that the chemical gets into the roots from the leaves. (If your not aware this is how it works the leaves take it to the roots through transpiration or whatever you call it where it takes the carbohydrates made in photosynthesis to the roots)

I would buy generic roundup at landscape suypply places it is much cheaper than roundup (unless your using roundup as a name for the chemical glyphosate). Make sure you get 41% glyphosate. You can buy it at landscape places for less than $50 for 2.5 gallons of concentrate and you mix 4 oz/gallon. I got the last gallon from a guy i have contract work done for a place i manage, he buy it 100+ gallons at the time so he gets a deal. I got him to get me some i paid him his price $15/gallon.

 

[johnk]

Thanks for that info Clem. Do you suggest tilling after a week and respraying to make sure I got all the seeds and runners??"?

 

[Pilot]

Roundup (glyphosate) is taken up thru the leaves--it will not affect the seeds. After it is taken up thru the leaves it is translocated internally to the roots, which it then kills.

Spraying after tilling won't do a thing unless there are some leaves exposed on plants that somehow would otherwise survive.

Spray it once, spray it thoroughly and you're good to go.

Roundup no longer moves thru the plant after 72 hours, so waiting longer to till than that gives no benefit.

Be sure to use a sticking (wetting) agent, one that is made for herbicides. Don't bother trying to use detergent, it won't work nearly as well as the stuff made for the purpose. The glyphosate I buy has the sticker in it; it costs about $5 more per 2.5 gallons than the stuff that doesn't have it.

 

[clemsonfor]

John and piolot , your both correct.

John if you spray after tilling and you hit a live root it will kill it by hitting it with roundup, not as well as leaves but that is a surface that can uptake something to the plant, it is a root afterall.

Roundup is not soil active and turns to harmless crystals once in soil so technically you can plant in the soil once sprayed, the danger comes in as your tender new growth may contact an leaf that still has residue on it that in the mourning dew rehydrates the herbicide thus transferring it to the new plant. This is the reason you see the warning on the bottle , like wiat 10 days to plant veggies etc.

Id wait in my opininon at least 5 days till it then wait 2 weeks for resprouts and new seeds to sprout and spray it again, that should get most of the stuff.

Piolot, you dont just have to hit leaves, green stems like on grasses and flowers can cause death, also you can girdle or cut a sapling and spray the stump when wet and fresh and that will translocate the poison to the roots for death. Leaves are optimum but not a hard fast rule. Woody stems not a problem, like my crepe myrdle i just spray around the base i dont care if i hit the trunk, it dosent do anything as it cant go through the bark/woody stem. Or if your spraying around your big oak tree so you dont have to weed eat just spray grass around it 10"s or so and dont worry about over spray onto the tree it is harmless to it, on the trunk that is.