Horticulturist (8)
I believe the answer is:
gardener
'horticulturist' is the definition.
(gardener is a kind of horticulturist)
This is the entire clue.
(Other definitions for gardener that I've seen before include "Tender of plants" , "Garnered by worker on cultivated ground" , "Horticulturist" , "Cultivator" , "One grows" .)