Reply to a question on weed control in a horse pasture containg some chicory.
The presence of chicory limits the herbicide choices very severely, because almost all the good broadleaf weed sprays will damage chicory.
However, all authorities do agree that flumetsulam (i.e. our product “Decision") is the No 1 herbicide choice for weed control in chicory. It will kill almost all of the weeds on your list, but alas not thistles. It’s probably not going to be all that flash against docks either, nor against larger ragworts, but I have had reports of reasonable success with Decision against smaller seedling and rosette stage specimens of those species.
For scattered larger thistles, ragworts and docks, your best practical option is to use spot treatment, and the product I’d suggest is our BuckShot which is applied around the base of the individual target plant as a dry granule. It avoids the problem of overspray. It’ll also kill clover (not a problem, in a horse pasture), and also chicory. But the chicory damage will be restricted only to the direct application site, so you won’t be inflicting big bare patches on your pasture. It’s inexpensive, easy to use, and safe for livestock … although remember that some poisonous plants incl ragwort do become palatable to stock as they die off. Ragwort is very toxic to horses, but when it’s healthy ragwort they will avoid it because it tastes awful. But as it dies off, the taste improves and no longer deters grazing. And it also actually becomes even more toxic to horses as it dies off. You can’t safely allow horses to remain in a paddock where ragwort has been treated with any herbicide. So either keep them out at least 14 days, or hand pull the ragwort instead and remove the pulled ragwort plants from the site entirely. Best time for hand pulling is late flowering, before the ragwort starts dropping seeds.
Sorry to be bringing you the bad news that there’s no single herbicide that will do everything in chicory-based pastures! But a combination of two products – Decision and BuckShot – will cover everything nicely. Just be very careful with that ragwort!