Garden feature maintained by wastrel, listlessly (7)
I believe the answer is:
trellis
'garden feature' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'maintained by wastrel listlessly' is the wordplay.
'TRELLIS' is hidden within the letters.
However, I am uncertain how this is indicated.
Can you help me to learn more?
(Other definitions for trellis that I've seen before include "Support for creepers" , "Framework supporting climbers" , "where climbers may be trained" , "Frame for climbing plants" , "Support for climbing plants" .)