How about doing a quick Q+E (at least I think E is the speed boost) right before you ward? I dunno if it works or not cuz I don't know Sona's Q range, but if it does it'll help you run away as folks expect to jump on the support just about the moment they ward, not before. But otherwise it's always best if you have backup and/or know the enemy is unlikely to be in that bush.
Usually in the laning phase as bot team, unless enemy jungler has a short CD+cost jump, you can get away with warding in front of dragon instead. That gives you vision of both dragon and their jungle entrance. Unless the jungler comes from down the lane or teleport directly into the bush, you'll see him coming and know when he leaves. Try to also get vision of the entrance to your tribush as well. Then, refresh the ward just before it expires, so you can sacrifice a few secs of duration for the knowledge that nobody's there when you ward.
