Topiary and lawn I replanned with BBC gardener (10,5)

I believe the answer is:
capability brown
'gardener' is the definition.
(famous English 18c gardener)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for capability brown that I've seen before include "Gardener" , "fellow good at planning growth" , "Landscape artist" , "Lancelot" .)
