hi I handle weeding and trimming for a living and i can tell you this,over the years i have learned there is no quick fix to weeds.if you were able to find the best weed killer it still doesnt take the weeds out from where they are growing and you have big dead ugly weeds in your beds and sidewalk etc. the best solution is to pull all of them by hand and begin a weekly spraying program to keep down the little ones that come back,because they will. I have a customer Right now who put in rock for the entire yard and went on vacation,came back and the weeds grew every square inch of the rock,weeds will grow anywhere end of story, they even had a very thick liner weedscreen.pull them and spray to maintain.

I think you are talking about the weed "Spurge" Even if you spray the weed, the seeds dry up and drop, and germinate later. When you pick them, (which is the best solution) they have this milky substance on them, which can make you itchy. I use a long screw driver to loosen the weed first, (around the root)so it comes right out. That spurge can grow anywhere, and it seems like it pops up overnight!! :)