The variation in essential oil yield and composition fromOlearia phlogopappa(Labill.) D.C. was examined. Three clones from Paradise Plains (PP), Elephant Pass (EP) and Buckland (BU) were studied over six months, and the Mount Wellington (MW) clone over 18 months. MW clones showed that juvenile leaves consistently contain more oil than mature leaves, peaking in the summer months. EP, PP and BU also reflect this trend. In all clones, leaves of increasing physiological age declined in essential oil content during summer and autumn. In the BU clone, leaves of both increasing physiological and chronological age peaked in oil yield in March. In PP, leaves of increasing chronological age gave a constant yield up to April, peaking in May. The yield from EP leaves rose to 2% in January, decreasing to 0.6% in May. The percentage composition of the major components of each oil varied from clone to clone over the summer period.