Heath genus; girl's name (5)
I believe the answer is:
I believe this is a double definition.
'heath genus' is the first definition.
(I've seen this in another clue)
'girl's name' is the second definition.
(Other definitions for erica that I've seen before include "Moorland plant, girl's name" , "Heathland shrub; girl's name" , "Heather's Latin name?" , "Plant of the heath genus" , "ling" .)