This needs to be up 100% of the time. It is free healing due to the HT and RG refreshes; use it on a tank and it should never fall off. There are some exceptions to the tank usage, mushrooms on Brackenspore for example, but generally that strategy will behoove you.
Another big advantage of lifebloom is the clearcast effect which grants a free Regrowth. Generally this should be used right away on a heavy damage soaking target like a tank; the refresh of the lifebloom is an added bonus.
That said, most of the healing comes from the initial cast, so it can be wise to save the Regrowth for a few seconds depending on the circumstances. For example, if it will be pure overheal, you’re in a boss transition phase, or you’re just before a damage spike, the Regrowth can go a long way in helping your situation.
Swiftmend + Soul of the Forest
The bonus granted by SotF should typically be used in conjunction with Wild Growth. WG gets an additional 50% potency, meaning it heals 24,564 HP to each of 5 targets at my current un-buffed gear level; that’s compared to 16,376 without the buff. At that potency, it’s slightly stronger than 5 rejuvs (23,328 each), but the mana cost is equivalent to 4. Add the GCD time you save and you’re looking at a nice throughput increase.
Use this to help heal through heavy raid damage, or when bug damage spikes affect more than one target, but make sure you use it often. In raid situations, you need to have a rough idea of how the raid’s health pool fluctuates over time. Plan to use your Nature’s Vigil with maximum uptime while still aligning the cooldown with critical moments.
Tracking Your Spells
Use an addon like WeakAuras or TellMeWhen to track your spells and CDs. Put notifications in places that you are prone to look when healing so that your awareness of these spells becomes seamless.