Recommendations about unusual borders for such flowers (6)
I believe the answer is:
tulips
'flowers' is the definition.
(I know this)
'recommendations about unusual borders' is the wordplay.
'recommendations' becomes 'tips' (tip can mean a recommendation).
'about' indicates putting letters inside.
'borders' suggests removing the centre (only the edge or border letters remain).
'unusual' with its centre removed is 'ul'.
'tips' going around 'ul' is 'TULIPS'.
'for such' acts as a link.
(Other definitions for tulips that I've seen before include "plants" , "Garden flowers associated with Amsterdam" , "Nice flowers, musically from Amsterdam" , "Slit up the Spring flowers" , "Flowering bulbs" .)