Maybe, leaves space in the middle of a string of beads (8)
I believe the answer is:
rosemary
'maybe leaves' is the definition.
(rosemary leaves are used as a herb)
'space in the middle of a string of beads' is the wordplay.
'space' becomes 'em' (in typography, a space as wide as a letter 'm').
'in the middle of' means one lot of letters goes inside another.
'a string of beads' becomes 'rosary' (rosary is a kind of string of beads).
'em' inserted into 'rosary' is 'ROSEMARY'.
(Other definitions for rosemary that I've seen before include "Grey-green herb" , "Fragrant evergreen shrub and herb" , "Herb - girl's name(s)" , "One or two girls" , "Shrub of the mint family" .)