European Pennroyal (Mentha pulegium) is an aromatic, mint family plant that has naturalized itself across the Western United States. Pennyroyal will readily establish in low fertility soils and thrives on moderate to regular watering. Be careful not to water too much though, as its rhizomes will readily colonize nearby garden beds. Easy to start from seed and extremely beautiful and fragrant during flowering. During its peak growth season in the spring, well-established root systems can also be easily divided.