Polylectic: visiting mainly Fabaceae, Lamiaceae and Asteraceae (Terzo; unpublished doctoral thesis). Terzo also reports that the species will visit Eryngium campestre (Apiaceae).
Ortiz-Sanchez & Terzo (2004) list Onopordum sp. (Asteraceae) as a forage source.
Mavromoustakis (1948; 1952) reports visitation to Vitex agnus-castus (Lamiaceae) and Rubus ulmifolius anatolicus (Rosaceae) in Cyprus.
Paulus & Gack (1990) have observed pseudocopulations of the male of X. iris with flowers of Ophrys spruneri in Greece and with flowers of Ophrys sipontensis (Orchidaceae) in Italy. Terzo states that to his knowledge, Xylocopa iris is the only known pollinator of these 2 orchid species