Not an exotic plant (6)

I believe the answer is:

simple

I'm a little stuck... Click here to teach me more about this clue!

'plant' is the definition.
(simple is a kind of plant)

I cannot understand how the rest of the clue works.

(Other definitions for simple that I've seen before include "Easily done/understood" , "Penniless pie seeker" , "Easily understood" , "Impels to be plain" , "Impels (anag.)" .)

I've seen this clue in The Globe and Mail.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.