Everything You Need to Know About Growing and Caring for Pennyroyal
If you’re looking to add a unique herb to your garden that not only smells great but also has useful insect-repelling properties, pennyroyal might be the plant for you. In this in-depth guide, we’ll explore everything you need to know about growing and caring for pennyroyal plants, from planting to pruning and everything in between.
An Introduction to Pennyroyal
Pennyroyal, scientifically known as Mentha pulegium, is a spreading plant with pale purple flowers that bloom in mid to late summer. The plant has oval leaves that emit a fragrance similar to spearmint when crushed. While pennyroyal is easy to grow, it can be invasive in certain regions, such as parts of California and Oregon, where it is considered a problematic species.
Pennyroyal Care Tips
Although native to Europe, the Middle East, and Asia, pennyroyal has become a naturalized exotic in North America. Here are some care tips to help you nurture your pennyroyal plants:
Light
Pennyroyal plants thrive in partial sunlight, but they can also tolerate full sun as long as they receive enough moisture. Aim to plant your pennyroyal in an area that receives at least six hours of sunlight daily for optimal growth.
Soil
Pennyroyal plants prefer moist, rich soil that has been amended with organic matter. However, they can also grow in clay or sandy conditions. The plant does not have a specific soil pH preference and can thrive in acidic, neutral, or slightly alkaline soil.
Water
Regular watering is crucial for healthy pennyroyal plants. The soil should always feel moist to the touch, and pennyroyal grows well in damp areas like stream banks.
Temperature and Humidity
Pennyroyal plants can adapt to both cool and hot summers, but they prefer humid conditions. Adequate irrigation can help pennyroyal plants thrive in dry climates.
Fertilizer
Avoid using chemical fertilizers on pennyroyal plants, as they can inhibit flowering. Instead, provide organic humus from leaf mold, manure, or compost to nourish the plants.
Types of Pennyroyal Plants
While there are no named cultivars of pennyroyal, there is a native plant called Hedeoma pulegioides (American pennyroyal) that has similar growth habits and cultural needs as Mentha pulegium.
Pruning and Propagating Pennyroyal
Regularly pruning pennyroyal plants is essential to control their growth and prevent invasiveness. You can propagate pennyroyal plants by splitting off root sections and replanting them or by rooting tip cuttings in moist soil.
Growing Pennyroyal from Seed
If you want to grow pennyroyal from seed, plant them in small containers filled with potting soil, covering them lightly with 1/8 inch of soil. Seeds need light to germinate and should sprout within about 21 days at 68 degrees Fahrenheit. Transplant the seedlings outdoors after the last frost date.
Potting and Overwintering Pennyroyal
Pennyroyal plants can be potted in containers of any size and material with good drainage. While they don’t require winter protection in their hardiness range, it’s important to cut back dried stems after they die back and move potted specimens to a sheltered location for the winter.
Encouraging Blooming and Dealing with Pests
Provide adequate sunlight and avoid over-fertilizing to encourage pennyroyal plants to bloom. While pennyroyal is relatively pest-resistant, keep an eye out for leafhoppers, caterpillars, and fungal diseases like powdery mildew.
Dealing with Invasiveness and Common Problems
Pennyroyal’s spreading habit can be both a blessing and a curse, as it may overtake other plants if not kept in check. If pennyroyal becomes a problem, consider tilling the soil or using non-selective herbicides to control its growth.
In conclusion, pennyroyal is a versatile and useful herb that can add both fragrance and functionality to your garden. By following these care tips and techniques, you can successfully grow and enjoy your own pennyroyal plants. Whether you’re a seasoned gardener or new to herb cultivation, pennyroyal is sure to be a rewarding addition to your garden.
