For Channel Animal, it seems, like said before, arcane reach, would do the trick (ranged touch spells), as for channel plants, a special entangle, wouldn't be so bad, or some kind of trap-like SA (like snare ?), where you get to either damage (reflexe), paralyzie (fort), or confuse (will) the target (summarize what druids can do with spells ..more or less) , since this abilities only seem to work once (first thing that touches the plants) ..again, a bonus feat would do fine