I urge man to cultivate a pelargonium (8)
I believe the answer is:
geranium
'a pelargonium' is the definition.
(I've seen this before)
'i urge man to cultivate' is the wordplay.
'to cultivate' is an anagram indicator (I've seen 'cultivating' mean this).
'i'+'urge'+'man'='iurgeman'
'iurgeman' anagrammed gives 'GERANIUM'.
(Other definitions for geranium that I've seen before include "Flower for a strange Maine rug" , "Popular flower" , "Pelargonium (loosely)" , "Flower - cranesbill" , "Cultivated cranesbill" .)