Since no answer here (except Mogh's comment) is right, I decided to handle it myself.
You don't have to run all the way through Nargor.
You don't need lvl 50 noobchars.
You can check if the flower is blooming, quickly and safely.
All you have to do is to get the access to Nargor and log off your char on the following, specific sqm, close to NPC Sebastian:


Note that griffinclaw (dry) is not visible at all while standing there, but it's not a problem.
As you can see, the blooming griffinclaw flower can be clearly seen. Low level char can be left there. This is the fastest, easiest and the most efficient way to check it.
Credits:
Mogh - for reminding me about that method
Jinrago Tibia (https://www.youtube.com/watch?v=L8eQ7f9Moh8 0:22 second)