Anyone willing to make this add on would be awesome. There may be one out there allready but not sure. I did some looking but didnt find what I was after.
Just like there is NPC scan that scans for rare npc's. Could there be an addon for specific herbs/ ore that did the same thing.
For instance - I am doing dailies and dont want to bother with picking every herb or mousing over every herb in my minimap to see if its a golden lotus or not. But if if poped up a msg GOLDEN LOTUS Node Found, Sure i would stop questing and go pick that bad boy up. Even better if it was possible to scan the zone or area that I was in would even be better!!
Carbonite does that, although the node database needs a lot of updating. The addon has a new maintainer, and he has other things ahead of this on the priority list, so it'll be a while.
I should clarify that Carbonite will generate a route for collecting herbs (or ore) based on a specific herb or ore, and based on its database of places where that herb or ore is known to spawn. As Phanx points out, no addon can tell you where something, specific or not, has spawned.
It's not possible for an addon to know when a tracking blip appears.
An addon can remember where you've actually clicked on an herb/mining/other resource node (or use a database scraped from Wowhead) to show you where nodes can spawn, but it can't tell you when there is an active node in one of those locations.
There used to be (maybe 5 years ago) an addon that tried to detect tracking nodes by constantly moving the minimap so that a different part of it was under the cursor, and checking if a tooltip was visible, but I don't know that it's still around, or that it still works, and in any case I'd imagine that it would make the minimap basically unusable, as well as make it very hard to do anything with the cursor (such as clicking on something) while it was running. It might still work, though, if you can find it.
It's definitely not possible for an addon to tell you when a node spawns outside the area shown on your minimap. The only way to do this would be using an external third-party program in violation of the WoW ToS/EULA, which would get your account banned.
You might consider using an addon like GatherMate (get GatherMate_Data too if you want a prebuilt database) and set it to show you only the locations where Golden Lotus is known to spawn. Then, you only need to mouse over herb nodes if they appear in one of the marked locations, and you can ignore all others.
Then I guess you're just stuck using that 0.5 seconds and 0.001 calories to move the mouse over the tracking blip and see what it is. If reading the tooltip is too hard, there are addons that can alert you when certain text appears in the tooltip, so you can just wave the cursor around and ignore the tooltip unless you hear the alert sound.