Fury of some upset landscape gardener (4)
I believe the answer is:
rage
'fury' is the definition.
(synonyms)
'some upset landscape gardener' is the wordplay.
'upset' says the letters should be written backwards.
'some' indicates a hidden word (some of the parts of the word are used).
'egar' can be found hidden inside 'landscape gardener'.
'egar' written backwards gives 'RAGE'.
'of' acts as a link.
(Other definitions for rage that I've seen before include "Extreme anger" , "Intense anger" , "Fit of temper" , "Temper - fashion" , "Fashionable" .)