Roundup can take over 2 weeks to move to the root tips to kill the plant.
Patience is a virtue.
Greg
Where do I buy that?
Yeah Since it has come back with a vengence after doing nothing to it in the last 3 weeks I am thinking the "let Roundup do its job " isnt working, with as much as I have put on everything should be dead. I will take a picture tomorrow after a last Roundup application and see what happens. but I think I am going to have to relocate the dirt to a different area without water and dry up the root parts, or set fire to the ground.I will keep everyone informed to what works
Cooking it under plastic for a few weeks might be your best bet. Also, i have found that some full strength bleach in a spray bottle goes a long way (and much cheaper than Round Up). It usually kills just about anything, however your mileage may vary. Good luck, were all counting on you.
-Kevin.
Over 2 weeks…
If there is anything green showing, hit it again.
Greg
Wow Dieseldude, thats a lot of pressure! I may wind up digging up half the yard, spraying it with Agent Orange, Bleach Boiling water or soil sterilizer , but theis dang plant will die!!!
I was introduced to roundup about 35 or 40 years ago, forget the exact date.
But I don’t forget the explanation, my landlord owned a farm that raised food and other stuff, even then the stuff was $100 a gallon for the concentrate (not the weak crap you buy now).
What they beat into my head, (besides the fact it was expensive and I should not waste it), was that the poison needed to travel from the leaves to the roots, and it can take over 2 weeks, and sometimes a few applications. I was to RESIST chopping the heads of the weeds off, as you could not tell how long it took for the poison to travel to the root tips.
They told me, just leave it alone, and eventually it will die, and dry up and blow away. After following their instructions, and waiting impatiently, it worked, the weeds never came back to the same spot, that PARTICULAR weed was indeed dead.
There are new versions of the stuff that “burn” the top of the weed, so people think it’s working faster, but the real “magic” of killing the root is the same slow process. You HAVE to leave it alone, and if after a couple of weeks, there is some green left, hit it again.
Actually, while it does take a lot of patience to keep staring at your nemesis, there is a lot less work involved since you never dig anything up or cut weeds.
Pete, while you said you waited 3 weeks, you also said you dug stuff up, I think you really are not giving this stuff a chance. Also check that you have at least the 2% concentration, nothing less… look on the container.
Greg
I was recently helping my son in Tampa with weeds growing between the bricks of his dry laid patio. I am normally a Roundup user but he asked a co-worker whose father installs paitos for a living. He recommended Spectracide so that’s what we used. It worked fast on the tops but only time will tell if it kills the roots as successfully as Greg mentioned that Roundup does.
Good luck,
Tom
Tom Bowdler said:
I was recently helping my son in Tampa with weeds growing between the bricks of his dry laid patio. I am normally a Roundup user but he asked a co-worker whose father installs paitos for a living. He recommended Spectracide so that’s what we used. It worked fast on the tops but only time will tell if it kills the roots as successfully as Greg mentioned that Roundup does.
Good luck,
Tom
Might this be a good place for double or follow up use. Kill with Spectracide, when nice and brown but still marking the spot of the plant follow with Roundup. You got to kill the green and then prevent the spread of seeds.
Look at me, entering in to a conversation about plants. There are friends that will question my sanity, of course they do anyway. My usual solution is concrete.
I was a biology major, 
It seems to me that once you kill the top there is no viable plant tissue to transfer the active ingredients to the roots and hopefully it is already there. If it regrows then that avenue opens again. I’ll check with my son to see how it’s working out.
Pete Said, "Yeah Since it has come back with a vengence after doing nothing to it in the last 3 weeks I am thinking the “let Roundup do its job " isnt working, with as much as I have put on everything should be dead. I will take a picture tomorrow after a last Roundup application and see what happens. but I think I am going to have to relocate the dirt to a different area without water and dry up the root parts, or set fire to the ground.I will keep everyone informed to what works”
Pete,
Re-read re-read re-read all three of my posts, all three of Gregs posts, and throw away your shovel you will win the battle with your weeds. Lastly, by relocating the dirt you’ll get to enjoy a whole new area for the weed flourish! Use RU or a generic brand with 41% glyphosate.
Tom said, "
I was a biology major,
It seems to me that once you kill the top there is no viable plant tissue to transfer the active ingredients to the roots and hopefully it is already there. If it regrows then that avenue opens again. I’ll check with my son to see how it’s working out.
That’s correct Tom. The Glyphosate will only work if the plant can Translocate the poison through living leaves to the roots.
Dr Percy Lilly my Botany professor would be proud of me.
I see that Spectracide has significantly different active ingredients, I’ll check them out when I have time. My chemistry is a little rusty.
Tom (Heidelberg College Class of '68)
Dan the reason for saying I was going to relocate the dirt was because in a different area of the yard I had the same plant and after digging it up and shutting off the drip to that area, nothing has sprouted. The main problem is an area where the plant has grown under the brick border into the grass, so even spraying the grass area where the plant is growing up has not been effective, since the plant still gets plenty of water along with the grass. I have read , re-read your posts and nextSaturday will be 2 weeks, so we will see how well the Roundup is working.
I am going to get some Spectracide and try that too since Roundup does not seem to be as effective as it should be. Do not know if there is an expiration date on it I will check tomorrow. Since this plant has a very soft, watery root, I am guessing it is just overpowering the roundup as it flows through the roots. Will do more research on it
Edited to add this from an article on how to kill it; . The species can be controlled in yards using ready-to-use herbicides. However, repeated treatments may be needed and long term management of large escaped populations will be costly. It went on to say the Ryhzomes can continue to sprout, even with several applications of Roundup or other herbicide weed killers