I would say it depends on your campaign focus. If the focus is on alchemy and material preparation, then having multiple skills makes sense (and you would likely have several skills for animal and mineral ingredients as well). This emphasises the focus, fosters specialisation, and details what needs to be detailed in the context.
However, if herbalism/apothecary is a secondary concern in your game, I would advise using a single skill (herb lore would sound good), with survival only being useful for herbs that are of immediate use in the wild - nourishment mostly, and perhaps avoidance of some poisonous plants (but no knowledge on how to actually gather and prepare them). Of course, herb lore is the main factor in herb gathering, preparation and use, but it does not help anyone actually *survive* in the areas where the herbs grow.
But I'm all for having a compact skill list, and furthermore, a skill list that is relevant to the specific campaign, not a generic, one-size-fits-all skill list.