A common plant (5)
I believe the answer is:
gorse
'a common plant' is the definition.
The definition and answer can be both plants as well as being singular nouns.
Maybe there's a link between them I don't understand?
This is the entire clue.
Can you help me to learn more?
(Other definitions for gorse that I've seen before include "Ogres (anag.)" , "Wild shrub with yellow flowers and sharp thorns, common on hillsides" , "Spiny evergreen shrub" , "Prickly shrub, furze, whin" , "Spiny heathland shrub" .)