Comparison of druid healing spells

Druids have available to them a number of different healing spells, some very mana-efficient, others providing a healing boost when needed.

Methodology
These tables show untalented healing values. If the druid has the talents for each spell, the relative comparison between the spells will remain similar, and if one is specced and not the other, that will skew the data in the obvious way. To give a feel for the effects of talents some entries contain a second value in parentheses next to them, representing what that entry would be with full talents in restoration tree.

We will calculate health restored per mana (HPM) and provide heal per second (HPS) figures for comparison, to give a sense of the use of each of these spells in actual healing.

Lifebloom has two elements: a fast ticking HOT (per second rather than per 3 seconds) and a larger heal as it expires (the bloom). Stacking it (up to three times) increases the HOT, but not the bloom. Consequently, there are several possible strategies. We will evaluate two of them below. One is sequential casts without stacking, while the other involves stacking lifebloom three times, and refreshing the stack repeatedly before the "bloom". Since efficiency is mainly a concern in longer fights, all the calculations below assume a long fight, where the mana cost of setting up a stack of 3 lifeblooms becomes insignificant. It assumes the druid using this strategy refreshes lifebloom every 6 seconds.

Comparison
Our first table gives the figures for the spells assuming no +heal whatsoever. Time is cast time plus spell duration.

So for zero +heal, casting lifebloom every 7 seconds provides the highest heal per mana. The picture changes dramatically when we have +heal, though.

As can easily be seen, stacking lifebloom and keeping it stacked not only becomes highly mana-efficient: it's healing per second also rises considerably. In practise, druids will stack 3 lifeblooms and a rejuvenation on the target, providing around 500 HPS, and use regrowth for additional bursts of healing. This is made even more mana-efficient by tree of life form, which reduces the mana cost of all these spells by 20%.