Mentha requienii
The smallest of the mints, this prostrate creeper forms a dense, mosslike carpet barely a quarter inch to one inch tall that spreads slowly to about 12 inches wide. It prefers partial shade and consistently moist, well-drained soil, performing best where it is protected from harsh afternoon sun and drying winds. The tiny rounded bright green leaves release an intense peppermint fragrance when brushed or stepped on, and are dotted with minute pale lavender flowers in summer. Use it between flagstones and pavers, along shaded pathways, in rock garden crevices, and as a fragrant filler for tight, moist niches with light foot traffic.