Once it’s planted, does it shoot up? (6)

I believe the answer is:

rocket

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'shoot up?' is the definition.
(I've seen this before)

I can't explain the rest of the clue.

(Other definitions for rocket that I've seen before include "Projectile; salad plant" , "Go up very quickly" , "that should take off?" , "Structure that flies by expelling gases - or a reprimand" , "Salad plant; strong reprimand" .)

I've seen this clue in the Evening Standard.

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