Cook nine basil plants (9)

I believe the answer is:

biennials

'plants' is the definition.
(biennial is a kind of plant)

'cook nine basil' is the wordplay.
'cook' indicates an anagram.
'nine'+'basil'='ninebasil'
'ninebasil' anagrammed gives 'BIENNIALS'.

(Another definition for biennials that I've seen is " Venice and Whitstable festivals".)

I've seen this clue in The Telegraph.

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