Pennyroyal Mentha pulegium 'Upright'

Water

Pennyroyal, also known as Mentha pulegium, should be watered deeply but infrequently to ensure healthy growth. It is best to water when the top inch of soil feels dry to the touch, which typically translates to about once a week. Depending on the weather and soil conditions, you might need to adjust watering frequency. As a guideline, provide the pennyroyal with approximately one gallon of water per week during the growing season. During the winter, reduce watering to every other week unless the soil is still moist from the previous watering.

Light

Pennyroyal prefers full to partial sunlight to thrive. The best spot for this plant would be in an area where it can receive at least six hours of direct sunlight a day. When growing indoors, placing pennyroyal near a south or west-facing window would provide suitable light conditions.

Temperature

Pennyroyal grows best in temperate climates with temperatures ranging from 60 to 70 degrees Fahrenheit. The plant can survive minimum temperatures down to about 30 degrees Fahrenheit, and a maximum of around 80 degrees Fahrenheit. It's ideal to avoid exposure to temperatures outside this range for extended periods to prevent damage to the plant.

Pruning

Pruning pennyroyal is essential for maintaining its shape and encouraging fuller, bushier growth. It should be pruned in early spring, just as new growth starts to appear. Removing dead or leggy branches can be done at any time of the year as needed. Regular trimming of the tips can help to keep the plant compact.

Cleaning

As needed

Soil

Pennyroyal, commonly known as Mentha pulegium 'Upright', thrives best in a soil mix that is rich in organic matter, with good drainage, and slightly acidic to neutral pH levels, ideally between 6.0 and 7.0. A mix of two parts peat or coco coir, one part perlite or sand, and one part compost or aged manure would provide the necessary nutrients and structure for growth.

Repotting

Pennyroyal should be repotted every 2 to 3 years to refresh the soil and accommodate its growth. It can be invasive, so keeping Pennyroyal in containers helps to manage its spread and provides an opportunity to divide the plant during repotting if it becomes too large.

Humidity & Misting

Pennyroyal requires moderate humidity levels, consistent with what is typically found in the average home or garden environment. It is not particularly demanding but should not be left in extremely dry air for prolonged periods.

Suitable locations

• Indoor

  Keep Pennyroyal in bright, indirect light and moist soil.

• Outdoor

  Plant Pennyroyal in partial shade and moist, well-draining soil.

• Hardiness zone

  5-9 USDA

Life cycle

Mentha pulegium 'Upright', commonly known as pennyroyal, begins its life cycle as a seed which, when sown in warm, moist soil, germinates within 10 to 20 days. Upon sprouting, the seedling grows into a compact, upright herb with a square stem, characteristic of the Lamiaceae family. As the plant matures, it develops fragrant, oval-shaped leaves and blooms in mid to late summer, producing small lavender to purple flowers that attract pollinators. After pollination, the flowers develop into four tiny nutlets that contain seeds for the next generation. In temperate climates, pennyroyal dies back to the ground in winter, but the root system remains alive and the plant regrows in spring. This perennial herb may also propagate vegetatively from cuttings or by natural layering, allowing for expansion of growth or new plant cultivation.

Propogation

• Propogation time

  Spring-Summer

• Mentha pulegium 'Upright', commonly known as Pennyroyal, is often propagated by stem cuttings. This method is popular due to its simplicity and high success rate. To propagate Pennyroyal using stem cuttings, one should cut a healthy stem from the parent plant, ensuring that it is about 2 to 6 inches (5 to 15 cm) in length, and has several nodes. The lower leaves are removed, and the cut end can be dipped in rooting hormone to encourage root development if desired. The cutting is then placed in a pot with moist potting mix, ensuring that at least one node is buried under the soil where roots can develop. The pot should be kept in a warm, bright area but out of direct sunlight, and the soil should remain consistently moist. Roots often establish within a few weeks, after which the new plant can gradually be acclimated to less-controlled conditions.