A lemon-scented leaf does not establish a plant's identity. Use the botanical label and flower structure alongside foliage when comparing an unfamiliar herb with mint.
Begin with an identifiable name
The translated expression drugs grass does not identify a botanical species. A seller may use a descriptive name for a lemon-scented herb, but the scent alone does not establish which plant it is.
Ask for a botanical label and keep it with the plant. Photograph the leaves, stem joints and flowers when comparing it with a named Mentha mint.
Compare several features
Leaf shape and fragrance are useful clues, especially when examined on healthy mature growth. They should be considered together with flower arrangement and the supplied identification.
Choose cultivation advice only after the name is clear. Claims that an unidentified potted herb will remove indoor pollutants or provide a particular medicinal effect are not a sound basis for selecting or using it. This comparison concerns plant identification and growing information.
Related reading: Mint Varieties: Comparing Labels, Leaves and Flower Spikes.