Herb — girl's name (8)
I believe the answer is:
rosemary
This clue is a double definition.
'herb' is the first definition.
(rosemary is a kind of herb)
'girl's name' is the second definition.
(I've seen this before)
(Other definitions for rosemary that I've seen before include "Herb with narrow leaves" , "Helps one to remember" , "Plant" , "Herb - girl's name" , "Herb for remembrance" .)