Plant in the spring after all danger of frost has passed in a location that will receive full sun to partial shade. Space plants 8-12″ apart in average soil that is well-drained. Plant height 4-6″. Does well in containers or mixed pots.
Pennyroyal makes a superb low-growing ground cover, because it is both very hardy and very ornamental. Requires little to no maintenance. Perfect for rock gardens with its tiny bright lime-green foliage that forms a dense mat that works well between stones. Attracts bees and butterflies. Deer, insect and mouse resistant.
Mint spreads by surface and underground rhizomes, so consider carefully when choosing your location. To curb the spread of the mint, consider planting in bottomless number 10 cans or small laundry baskets. Mints like to be watered deeply, rather than watering lightly more often. In the fall, cut your mint plant back to the ground so that it will be more prolific the next spring.
Pennyroyal mentha pulegium
Pennyroyal, a perennial, is one of the most fascinating and unique members of the mint family, even sporting the characteristic square stem. It is extremely useful as an insect repellent because bugs positively hate it, and can be rubbed on the skin to that purpose, or put in bedclothes or the closet to make any unwanted creatures flee. Pennyroyal leaves are used in natural flea repellent products. Try placing some bundles of Pennyroyal in your pets bedding. It has a very distinct scent that is reminiscent of mint but with a stronger odor of camphor. Ingestion of this plant is strongly discouraged.
In medieval times Pennyroyal was thought to relieve itches, nausea, headaches and congestion, and to soothe the feet when put in the shoes during a long journey. It is now medically demonstrated that pennyroyal, as a mint, is indeed a stimulant. In more recent times, pennyroyal oil has been taken to induce menstruation or to cause abortion. The oil found in Pennyroyal contains a toxic chemical that is considered a poison. Just a small amount of concentrated oil can cause convulsions or comas. While the small amount of oil that might be found in drinking it as a tea might not hurt you, we recommend substituting peppermint tea, which is perfectly safe, instead.