Blue dots = herb patches to be discovered by L-rod exploration
Red dots = monsters/danger zones
P.S. since this is not really my guide, I'm not going to claim Nation gold for it. (urgg needs time to get used to the new name) I use this whenever I go exploring for herbs there.
[Image: http://i221.photobucket.com/albums/dd59/ruuuka/mabi/1.jpg]
[Image: http://i221.photobucket.com/albums/dd59/ruuuka/mabi/2.jpg]
I noticed if you want poison herbs, you have to go to the areas of the cave that are blocked by doors. They exist outside that area as well but very rarely.
For more information on the doors and other things in Solea: Solea (Cave Path) - Mabinogi World Wiki