The article is devoted to the analysis of the vegetative and bestiary poetics of Guy de Maupassant's late psychological novel "Our Heart" (1890), which lacks the proper attention of literary scholars both in France and abroad (scientific reflection is focused on short stories and novels of the heyday of Maupassant's realism). Therefore, its poetic study and introduction into the modern literary context is an actual scientific task. The purpose of the article is to define the semantics and symbolism of plant and bestiary imagery in the artistic structure of G. de Maupassant's novel "Our Heart" and to establish its functions in the realization of natural/artificial opposition, that is conceptual for the novel. The research was carried out in the framework of the structural-semiotic method of analysis of the artistic text. The analysis of the novel from the point of view of the artistic functions of floral and zoomorphic imagery proved the special place of these tools in deepening the psychological picture and expressive-emotional expressiveness of the images of the protagonists: André Mariolle and Madame de Burne. The range of these tropes is from vegetal and zoomorphic comparisons and metaphors to elaborate zoo- and dendroanthropomorphic images (Michelle de Burne is first a ‘bird of paradise’, a ‘wild bird’, then a ‘hawk of prey’ and, allusively, an ‘ostrich’, and also an old tired ‘horse’, a ‘nag’; Mariolle – is a ‘trapped wounded animal’, a ‘thrush in a cage’, a ‘small fish caught in a net’). The plant analogue of the heroine is a man-made flower garden, which gradually withers and decays, as her love for Mariolle fades away. Michelle's image is accompanied by numerous floral details that acquire a metaphorical meaning (these are cultural flowers of selected varieties – roses, orchids, carnations, geraniums, lilies of the valley, chrysanthemums, lilies etc.). In contrast to the “artificial” Michelle, the image of the “natural” Elizabeth is associated with wild forest plants – violets, gorse etc. The protagonist is correlated with ramified dendrosymbolism (chestnut, beech, oak, linden etc.) and the image of the forest as a secret liminal space. The symbolism of the wild forest is opposed in the novel by the symbolism of an orderly garden (as one of the options for embodying the natural/artificial opposition). Vegetal and zoomorphic images not only accompany the characteristics of the characters, but are also closely intertwined, passing one into the other (the anthropomorphic image of fused trees turns into the image of a battle between a predatory beast and its victim, plant juices become living blood). Subjective signs of the main character's “artificiality” are the images of stone flowers and stone animals decorating the central spatial locus of the novel – Abbey Mont Saint Michel. So, florisms, dendrisms and animalistic images in the novel perform a characteristic function, convey the dynamics of the feelings of the protagonists, acquiring a metaphorical meaning, and fill the landscape with symbolic details.