A court beset by a hundred and one plants (5)
I believe the answer is:
cacti
'plants' is the definition.
(cactus is a kind of plant)
'a court beset by a hundred and one' is the wordplay.
'court' becomes 'ct' (abbreviation used in road names).
'beset by' is an insertion indicator ('beset' could historically mean 'cover').
'a hundred' becomes 'C' (Roman numerals).
'and' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'a'+'ct'='act'
'c'+'i'='ci'
'act' inserted into 'ci' is 'CACTI'.
(Other definitions for cacti that I've seen before include "Plants native to arid regions" , "Spiky plants found in deserts" , "Spiny desert plants" , "Leafless succulents" , "flowers" .)