They should have really found a way to buff this. 

What determines a "magical plant?"

Most basically, an herbalist would almost certainly know the key components of a Potion of Healing. Moreover, the DMG suggests between 75% and 25% of "components needed for a potion" to be available in a particular location, however, this implies that the party is using "mundane" methods of finding these things.

I am running what will (eventually) settle into a "West-Marches-Like" campaign where the adventures are very episodic and the party will have a bastion and expected downtime, as well as, potentially, multi-night stays in either remote or small town type settings where they may reasonably craft Common potions or find ingredients.

Clearly this spell has virtually no combat utility, but am I wrong to think its potentially underrated to have this prepared for purposes of gathering ingredients, or even ritual-casting in the evening to locate Game Animals and thus forego the need for rations while on expedition?

(nevermind the "obvious" usage of something like searching for a beast or plant creature thats been terrifying a village)