Involved in the production of floral volatile phenylpropanoids in flowers of fragrant cultivars (e.g. cv. Mitchell and cv. V26) from cinnamic acid, a common precursor with the anthocyanin biosynthesis pathway involved in flower pigmentation (By similarity). Methylates caffeoyl-CoA to feruloyl-CoA, also able to methylate 5-hydroxyferuloyl-CoA (PubMed:26620524). (E)-caffeoyl-CoA + S-adenosyl-L-methionine = (E)-feruloyl-CoA + H(+) + S-adenosyl-L-homocysteine (E)-5-hydroxyferuloyl-CoA + S-adenosyl-L-methionine = (E)-sinapoyl-CoA + H(+) + S-adenosyl-L-homocysteine Binds 1 divalent metal cation per subunit. Aromatic compound metabolism; phenylpropanoid biosynthesis. Mostly expressed in petal limbs and tubes, and, at low levels, in stems, roots and leaves. Accumulates during flower development with highest levels in open flowers, at anthesis, and fades out as flowers are senescing. Circadian-regulation with peak levels occurring at the end of the light period in flowers. Belongs to the class I-like SAM-binding methyltransferase superfamily. Cation-dependent O-methyltransferase family. CCoAMT subfamily.