Having insipid character, like a neglected garden (5)
I believe the answer is:
weedy
This clue is a double definition.
'having insipid character' is the first definition.
'like a neglected garden' is the second definition.
(Other definitions for weedy that I've seen before include "quite unlike Charles Atlas" , "like an untended flower bed?" , "Scraggy" , "Thin, puny (colloq.)" , "wimpish" .)