Sweet Gum and Persimmons sprouts

What is the best herbicide to spray pastures with that won't kill grass but will kill them?

There isn't one that is great in pasture. I believe Dow has a new one coming out that includes picloram but isn't restricted use that would do ok. Sweetgum is difficult to kill without adding imazapyr, which isn't very grass friendly.

Crossbow

If they are small, 2,4,d should kill them. If they've already gotten big it probably won't completely kill them.