Flower shirts (4)

I believe the answer is:

tees

This clue is a double definition.

'flower' is the first definition.
(River Tees)

'shirts' is the second definition.
(T-shirts)

(Other definitions for tees that I've seen before include "River on which Middlesbrough stands" , "sand-hills" , "Golf pegs" , "River of north-east England" , "Durham's river" .)

I've seen this clue in The Telegraph and The Times.

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