Frail first of azaleas in gardens pulled up (4)
I believe the answer is:
weak
'frail' is the definition.
('weak' can be similar in meaning to 'frail')
'first of azaleas in gardens pulled up' is the wordplay.
'first of' says to take the initial letters.
'in' is an insertion indicator.
'gardens' becomes 'kew' (Kew Gardens in London).
'pulled up' says the letters should be written backwards.
The first letter of 'azaleas' is 'a'.
'a' going into 'kew' is 'kaew'.
'kaew' in reverse letter order is 'WEAK'.
(Other definitions for weak that I've seen before include "Spent" , "Undefended" , "Feeble or frail" , "lacking intensity?" , "Easily led" .)