In this essay, the paradisal visions presented in John Donne's lyric "Twicknam Garden" and in the actual garden at Twickenham Park belonging to his patron Lucy, Countess of Bedford, find mutual illumination through my readings of the conventional European garden across periods and artistic media. Without evidence from the garden, readings of the poem reach a dead end in the exhausted tropes of Petrarchan love poetry. Without evidence from the poem, readings of the garden misidentify it as a baroque model of the Ptolemaic cosmos. Considering the two together, I offer a case study of horticultural ambitions under conditions of limited resources and reveal how the poem—by way of an imagined fountain absent from the garden itself—imports Parnassus into the paradisal space it constructs, an eroticized humanist vision of the medieval Garden of Love. Donne's lyric creates a refuge for poets from the limits of Petrarchism and patronage, while still playing the courtly game.