Make a perk available to rangers/druids to seek/track certain plants. As people of the wild they would know what plants grow where and have the ability to find them. This could even be a level 8 perk for druids only (like the rogue perks).
Although I think having perks similar to rogues for Druids may be overpowered, give this to a high level Druid or ranger as it would be a great boon to them, RP and Mechanically.
Really not a good idea. One, there's plants everywhere anyway. Two, when I played alchemists, I spent quite a bit of time trying to hide my gardens from druids and rangers so they wouldn't go looting the place. If anything it would be good to see some city farms and gardens designed to be more inaccessible to wilderness types.
I think everyone pillages everyone's plantations at this point. Its actually insane. Even when you think you've found somewhere isolated, you come back two days later and all your plants have been raped and pillaged.