Bayer Advanced Brush Killer Plus Concentrate is not an insecticide so it should not harm bees. We suggest applying any product when bees are not foraging to lessen exposure.
Per the product label on the Bayer Advanced Brush Killer Plus Concentrate there is no set time frame after it rains to apply, but you would want to wait until the ground is dry and there is no water puddled up. You would also need to be sure there will be no rain or water for 4 hours after application so the product has time to dry.
Bayer Advanced Brush Killer Plus Concentrate is more for woody brush and vines. While it could kill grasses it was sprayed to we cannot recommend it for this use. For monkey grass, we would recommend spot treating with a glyphosate product such as Gly Pho-Sel Pro 41% with Surfactant
According to the manufacturer, after using the Bayer Advanced Brush Killer Plus Concentrate the re-entry is 8 weeks per grazer. Bayer Advance does NOT recommend applying their products in pasture areas.
Adding a surfactant to Bayer Advanced Brush Killer Plus Concentrate is fine and can increase the effectiveness but on the label is does not specify it is required.
If you are just brushing the Bayer Advanced Brush Killer Plus Concentrate onto the stump directly it should not effect other plants in the area.
It would be recommended to wait 6-8 months before replanting after application of Bayer Advanced Brush Killer Plus Concentrate.