Plant that flowers, ending around the middle of July (5)
I believe the answer is:
tulip
'plant that flowers' is the definition.
'ending around the middle of july' is the wordplay.
'ending' becomes 'tip'.
'around' is an insertion indicator.
'the middle of' indicates the central letters.
The centre of 'july' is 'ul'.
'tip' placed around 'ul' is 'TULIP'.
(Other definitions for tulip that I've seen before include "Spring-blooming plant" , "Flower of the Netherlands" , "Bloomer" , "Spring-flowering bulb" , ""Dutch" flower" .)