The "Triple Strike" product contains dicamba, which can affect underlying roots of trees and shrubs if applied incorrectly, or after repeated use, especially in coarse soils or gravel. Roundup will not typically present these issues. It should work for you if applied according to directions, although it can take several weeks to see the control.

I just applied Spectracide to my lawn. When will it be safe for pets to walk in that grass, or to lie down in the grass? I would like to water the yard to wash any residue off the blades. So, how long before it is effective on dandelions and simple broadleafs? No thistles, crabgrass, etc.

Theoretically once one of these poisons has dried, or in 24 hours after application, your lawn is "safe" for children and pets to walk on. There is some research that indicates these poisons are still there, on the soil, for many days after application and is in the water you drink, at least according to the EPA ground water research people.