Plant producing hop tree oil (10)

I believe the answer is:

heliotrope

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'plant' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

'producing hop tree oil' is the wordplay.
'producing' indicates anagramming the letters.
'hop'+'tree'+'oil'='hoptreeoil'
'hoptreeoil' is an anagram of 'HELIOTROPE'.

Can you help me to learn more?

(Other definitions for heliotrope that I've seen before include "fragrant flower" , "shade of purple" , "Plant" .)

I've seen this clue in The Hindu.

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