When Erasmus Darwin announces that “the general design” of The Loves of the Plants “is to inlist Imagination under the banner of Science” (ii), an echo of the Song of Solomon (itself a touchstone for eroticized botanical imagery) reveals how charged the relationship is: “his banner over me was love” (2:4). This essay argues that taking The Loves of the Plants seriously as an erotic work reveals the essential importance of desire to the evolving diversity of vibrant life it envisions and to the interdisciplinarity it achieves. Not only does the poem popularize the Linnaean sexual system of taxonomy by infusing it with sensibility, creating a landscape driven by desire. The form of the poem makes a mixed marriage of art and science, verse and footnotes, in a tantalizingly episodic (non‐)structure which could be called pornographic. The relationships between the male and female parts of an overwhelming variety of flora are much more varied than the conventional gender roles later critics have often ascribed to the poem. Yet, while each vignette offers another sexual permutation, the cumulative effect blurs variety into sameness, an effect earlier recognized by John Cleland in Memoirs of a Woman of Pleasure. Cleland extends the boredom to style, citing the flatness, in inevitable repetition, of the vocabulary of pleasure. The descent of Darwin's poetry into unfashionability under Wordsworthian aesthetics is also the demise of an erotic interdisciplinarity. In addition to the stylistic simultaneity of variety and sameness, Darwin's footnotes, epic similes and tangents are driven from topic to topic by a kind of unchaste curiosity which flattens borders demarcating species, subject headings, legitimate attractions. “The Loves”, both desire and the poem itself, “laugh at all, but Nature's laws” (IV:486). Even Nature's laws play loose with categories, as pollinating insects are seduced by flowers. This article examines how The Loves of the Plants envisions a continuum of life forms and of disciplines by portraying and performing cross‐species erotic interaction. Personification of vegetable reproduction invites readers to conceive of their own desire in botanic terms (as, indeed, readers and parodists did). Fascination with hybridization epitomizes both Darwin's poetry and his science, from the remarkable love affair between nightingale and rose which produces the bird‐flower offspring fantastically described in Loves, to the painstaking study of cross‐breeding in the evolutionarily crucial chapter “Of Generation” in Zoonomia.