Heading for California, company following different boat leaves (7)
I believe the answer is:
tobacco
'leaves' is the definition.
(tobacco leaves)
'heading for california company following different boat' is the wordplay.
'heading for' indicates taking the first letters.
'company' becomes 'co' (abbreviation).
'following' is a charade indicator (letters next to each other).
'different' indicates anagramming the letters (letters placed in a different order).
The first letter of 'california' is 'c'.
'boat' anagrammed gives 'toba'.
'c'+'co'='cco'
'cco' put after 'toba' is 'TOBACCO'.
(Other definitions for tobacco that I've seen before include "Controversial plant grown commercially" , "Leaves to smoke" , "Nicotiana tabacum" , "Cigarette filling" , "Dried leaves for smoking" .)