19 shaman solo with root

[Yttrium]

Just hit 19 on my shaman, currently in Oasis hunting croc-o-diles. I have pretty good gear for an un-twinked newbie and I have had success up to this point smashing things with some dots and healing up afterwards. At what point do I start to transition to root / dot scenario?

I tried this a bit in Kurns and root seemed unstable at best. Do I need to wait for higher level root? Should I be targeting lower level mobs? My dots at 19 tick away pretty slowly, I think if I can figure root out I can do 2-3 crocs at a time with root-dot-med rotation.

Thanks!