There are 19 pure but highly variable species within the genus Mentha. Crosses and re-crosses have produced more than 2,000 named varieties, though there are five basic species that are most important. One is called Mentha spicata, or �spearmint.� Spearmints are highly variable in scent, but all have lavender flowers that occur in tall pointed spikes.
The wrinkled leaf form of Mentha spicata that we sometimes call �Kentucky Colonel� is found naturalized throughout Central America and the southwestern United States, as noted in The Big Book of Herbs, �wherever the conquistadors went. After Ferdinand Magellan claimed the Philippines for Spain in 1521, the herb was transported there. This form of spearmint deserves to be called �conquistador�s footprint.��
Almost all mints relish moist, fertile soil in full to part sun. Generally, mint is a shallow-rooted plant with medium to high water requirements. Because they spread so rampantly throughout the garden, mints of all kinds are recommended for container growing. They become root-bound very rapidly, so division and re-potting is essential to good maintenance.
Kentucky Colonel Mint, however, has been noted as somewhat less invasive and easier to control than most of its relatives, even when planted in the ground.