The art of the Achaemenid Empire flourished in Ancient Persia from the 6th to 4th centuries BCE, and featured stone-carved monumental structures adorned with recurring zoological and floral patterns. Such representations clearly had a symbolic meaning intimately connected to religious expression and the will of deities. Considering the lack of any comprehensive analysis of botanical features, we investigate the recurring plant patterns and the variety of plants depicted. An analysis of the documentation referring mainly to monuments in the two main capitals of Darius I, Persepolis and Susa, showed the presence of certain repetitive elements, such as the so-called rosettes (composed variously of Asteraceae capitula and Nymphaea flowers), palms (Phoenix dactylifera, the tree of life), pines, flowers or bunches and metamorphic elements. Some plants are described in this paper for the first time in the context of Persian iconography, such as Mandragora officinalis in offering scenes as a symbol of fertility and protection against evil spirits, Pinus brutia var. eldarica as a symbol of immortality and elevation to the gods, and the capitula of Matricaria/Leucanthemum as solar symbols. Further interesting elements include cf. Myrtus communis in some crowns and probably cf. Ephedra sp. in offering scenes. Achaemenid art was deeply influenced by the Zoroastrian religion of ancient Persia with its great attention to nature as well as by the nearby civilizations of the Mesopotamian area and Egypt. Most elements were also associated with psychotropic or medicinal attributes, which contributed to their position as symbols of power.