Steve from Jamestown, Ky writes
Johnsongrass can be a nuisance and hard to get rid of. Unfortunately, there is no chemical labeled for it in pastures. You can mow it as low as possible and/or apply a Glyphosate product such as Roundup Pro Concentrate to spot treat, but even then you might only get suppression. We would also recommend contacting your local cooperative extension office and speak with a Master Gardener to check if they are aware of a successful product.
Answer last updated on: 07/10/2017