So for Mining and Botany, there are 'special' nodes that only spawn at certain in-game times/in certain locations. This site lists these nodes, their spawn time and where to aim to harvest them (also what star level the item is). Great for planning out your next harvesting adventure.

Link: http://www.ffxivclock.com/#/

Here is a list of Ephemeral, Unspoiled, etc nodes for Heavensward:

https://docs.google.com/spreadsheets/d/1WE-JKUCI0ppcF5lfcML_lfYsf1QRZkTXFDU0nkN-Bn4/edit?pli=1#gid=0

https://docs.google.com/spreadsheets/d/1z4K0-ScWDP8BRDSkheeh0R9Bdo7aQ3p1zgvP6EI2M9E/edit?pli=1#gid=0