Regularly grow rushes and furze (5)
I believe the answer is:
gorse
'furze' is the definition.
('gorse' can be a synonym of 'furze')
'regularly grow rushes' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'grow'+'rushes'='growrushes'
The alternate letters of 'growrushes' are 'GORSE'.
'and' is the link.
(Other definitions for gorse that I've seen before include "I'm always blooming" , "Yellow-flowering shrub" , "Spiny evergreen shrub" , "Wild shrub with yellow flowers and sharp thorns, common on hillsides" , "Moorland shrub" .)