Type of card dope punched by energy plant (4,5)

'plant' is the definition.
(reed grass is a kind of plant)

'type of card dope punched by energy' is the wordplay.
I cannot really understand how this works, but
'dope' could be 'grass' (synonyms) and 'grass' is present in the answer.
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is present in the answer.
'card' could be 'red' (red playing card, as opposed to a black one) and 'red' is found within the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?