Flowers went among balloons (10)

I believe the answer is:

speedwells

'flowers' is the definition.
(speedwell is a kind of flower)

'went among balloons' is the wordplay.
'went' becomes 'peed' (both can mean urinated).
'among' is an insertion indicator.
'balloons' becomes 'swells' (balloon can mean to swell).
'peed' inserted inside 'swells' is 'SPEEDWELLS'.

I've seen this clue in The Guardian.

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