Each supp does fall under a catagory, and there's five. Natural, protective, utlity, offensive and curing. It's often very clear which is which, once you get moonblessed or if you're observant with moon phases.

Natural supps are call of the wild, liveoak, entangle, decompose, thornheart and spike growth.

Curing is stuff like mend and refresh.

Protective is carapace/protection from metals, armor of thorns, etc.

Utility supps are things like detect invis.

Offensive are thorns, sunray, telluric surge, the hunt - basically anything offensive not already under 'natural'.

Some areas have more than one CotW. What they are, where they are, is for the druid to discover. Sometimes there's a 'booby' CotW, or something it's just the same CotW in a different jacket. Pre-hasted ones can't be sped up more, they've got the 'haste' effect on them. They can be slowed, permanently removing said effect though. That's how I found out which ones were hasted.

Thornhearts are killed by extreme environments (hot, cold, etc). Spores are the same, but with the addition of water. There are some skills/spells that will remove or hinder spores, and a few niche ways to cleanse thornhearts. All up for experimentation. Fight a druid mob if you want the supp on you, they'll do it often enough.

Yhorian