Mustard refers to plants in the mustard family, especially species with small, vivid yellow flowers and pungent seeds used for seasoning. In poetry, wild mustard often evokes uncultivated countryside, roadside color, and beauty available without cost. Its golden blooms may also be compared to money or treasure, suggesting that nature offers a different kind of richness from material wealth.

“Wild mustard” commonly refers to several related flowering plants, often including field mustard, which grows readily in disturbed ground, fields, and along roads. Mustard’s yellow color makes it especially useful as an image of gold, sunlight, cheerfulness, or springtime abundance. In Reese’s poem, the plant contrasts with “tears” and the speaker’s later sense of poverty, helping develop the poem’s central contrast between spiritual richness and material lack.