Went off to tank Nexus yesterday to help out a guildie, a resto druid, with gear. Turns out she was geared to the teeth with a mix of 10 and 25 Naxx gear on top of some BC purples, but the healing mace off the last boss was indeed an upgrade for her, yay!
But here we had a well geared healer struggling through Nexus with an overgeared group. I popped up recount halfway to look at what heals were being tossed around only to see regrowth 35%, healing touch 10%, lifebloom somewhere in the middle of those and poor rejuvenation and wild growth way down at the bottom. No sight of nourish. As those familiar with druids might imagine there could be some trouble with healing raid damage and you would be right.
So let's get to it then, how can a druid best utilize their various spells to heal efficiently and easily. I often feel when healing on my druid that I am not alone, those hots ticking right and left on people I healed a few seconds earlier often leave me wondering if someone else was casting heals. Perhaps I am just weird.
First off you have your tank, you will want to plop a rejuvenation on them and keep it there. I generally apply this just before the pull if not right after to give myself a little buffer. Similarly to prayer of mending or earth shield, rejuvenation can be interpreted by the tank as a nonverbal, "I am ready for you to pull". If there is concern about pulling threat then hold off a little, but it is usually never an issue with an experienced tank.
If you find your tank taking a little more damage than your rejuvenation can keep up with then toss on a stack of lifebloom. Add additional stacks as needed to keep up with the damage, no rush. Stacking lifebloom slowly is actually beneficial since you can let it roll longer without a bloom and without incurring any additional mana cost from overwriting existing stacks. Don't reapply after 3 stacks, go ahead and let it bloom.
Now there will be times when a stack of hots won't be enough to keep the tank up. This is where I will throw in a nourish. If there is more healing required I will cast a regrowth and then nourish so there is that one additional heal over time ticking. I will also use wild growth as an additional heal over time. With 4 hots running on the tank, plus nourish thrown in once in a while that will handle most anything.
The same concept applies to multiple tanks it just requires a little more work to keep track of your hots on more than one target.
For emergencies there is nature's swiftness and swiftmend. I use nature's swiftness 99% of the time with a healing touch to let off the largest heal possible, the other 1% I hit it on accident and use it on a nourish. I generally use swiftmend on top of rejuvenation since there isn't the time to cast regrowth in these types of situations. These are for the times when you need to get off a large heal instantly to prevent a death. More often on non-tanks that don't have a buffer of hots running on them.
While your healing your tank other people are probably going to be taking damage. If it is just one person toss a rejuvenation on them and maybe one stack of lifebloom and then move on. If they need a little more toss a nourish on them. If they have pulled threat and need more attention treat them as you would a tank with a full stack of hots and frequent use of nourish. Don't give them too much attention if there are others that need healing, but do your best. If someone makes a habit of taking additional damage then feel free to mock them.
If many people are taking damage it is time to let off a wild growth. It is easiest to just run up and cast it on yourself rather than worry about who to put it on. It figures out who to heal on it's own anyway. If that it not enough alone I will also toss a rejuvenation on top of it and perhaps a lifebloom.
The most important distinction to make when healing non-tanks is whether they got hit once and will be able to recover slowly with a hot or if they are continuing to take damage and require more attention. This is something that comes with experience.
Druid healers are proactive rather than reactive, we heal before someone needs it. Since our hots require time to provide the same effect as a single large heal. Our hots also don't start healing right away, it takes until that first tick for any healing to occur. Which also means if you spam rejuvintation it will never do any healing because it resets the timer.
Often times we are going to have hots ticking when they aren't really needed, but that is to be expected and our overhealing as a result is usually quite a bit lower compared to other healing classes doing reactive healing where they start to heal after the damage has been done.
In general druid healing is very laid back and done at a fairly slow pace. Unless something goes wrong we toss a heal over time here and there and enjoy the view. Enjoying the view is also very important to us since we need to be paying attention a bit more than other healers so we can anticipate where healing will be needed. If you see someone has pulled threat go ahead and get the hots rolling while the mob is still walking over to them. Keeping an eye on what is going on can avoid those situations where a large heal is needed right away, those types of situations a druid is not as well suited for as other healing classes.