Per the Spectracide Weed and Grass Killer with Extended Control RTU Product Label, "Do not allow people or pets to enter the treated area until sprays have dried", and "Do not apply this product in a way that will contact any person or pet, either directly or through drift. Keep people and pets out of the area during the application."
is a non-selective herbicide, which means it will affect any plants that you spray with it. You would need to be very careful treating around desirable plants so that you do not spray flowers, shrubs, etc. directly or get any drift onto them.