katherine2 said:Thistles are known to be a relatively difficult weed to kill; however, to prevent the spread of more thistles, one should attempt to kill existing thistles before their seeding season. Since thistle root systems can continually grow new thistle plants, the best way to kill them in a single effort is to first cut the plants down, as close to the root as possible. Then, cover the area where the plant had been with a thick, dark covering, such as a tarp or old carpet, which will not allow sunlight to penetrate or new plants to spring up. Over several weeks, this should kill the plant.
frankrichards16 said:I use 2-4D weed killer. It will not kill daylilies (monocots), but it does a good job on thistle (broad leaf weed). If you use a concentrate, make sure you add the recommended amount of water. An incorrect "heavy" mixture can kill everything (kind of like Roundup).
Of course, 2-4D will not kill grass.
Bonehead said:Forgive me for asking, but wasn't 2,4-D the major ingredient in Agent Orange? A bit scary for me, but I'm not a chemical fan and plead general ignorance.
frankrichards16 said: I prefer using 2,4-D, not the mixture weed & feed.
From what I have read, St Augustine grass is sensitive to 2,4-D
This probably means that in the right dilution, 2,4-D is OK?