The article deals with the folk beliefs of Ukrainians about the origin of plants (herbs, flowers, bushes, trees) based on etiological legends and song folklore (carols and ballads) that emerged during the period of paganism and after the introduction of Christianity. In particular, the article highlights the folk etiology of such plants as poplar, pine, sycamore, alder, birch, aspen, willow, pear, blackthorn, elderberry, wheat, peas, nettle, basil, tobacco, periwinkle, garlic, horseradish, thistle, and others. Different layers of the Ukrainian traditional worldview offer different versions of the origin of plants. In the period of paganism, the creator of the plant is a human being. In the legends of this period, a human turns into a plant as a result of a spell cast by another person, through a voluntary decision to become a plant to atone for his or her own sin, or through the raids of the Crimean Tatars. With the advent of Christianity, or rather, with the borrowing of the dualistic apocryphal tradition, God and the devil, as well as Christian saints, are already demiurges in etiological legends. In Christian (apocryphal) etiological legends, plants useful to peasants (primarily vegetable gardens, orchards and grain) were considered to have been created by God. In contrast, plants interpreted by Ukrainian traditional society as dangerous or harmful were considered to have been created or spoilt by the devil or Judas. The villagers evaluated plants from a utilitarian point of view – whether they were potentially useful to the villager (they could be eaten, used for healing or building) or harmful (they poisoned, baked, pricked, overgrown with weeds in gardens and fields). Plants that were neither harmful nor useful were not noticed at all – Ukrainians were only interested in talking about things that directly affected them. Exceptions were plants with an unusual appearance, such as the colourful pansy flower.