Ephemeral nodes spawn at certain times during the day, and last for a 4 hour period in that time. You can respawn the node by walking up to one from each node pair and then leaving it, giving you tons of respawns of the node.

But at 2 furymint per potion, and the ephemeral nodes being a 4 hit, it's a tall order to try and supply a raid team with one gatherer.