If you’re a fan of the band Nirvana, you’re likely familiar with this plant from the song “Pennyroyal Tea.” There are two main types of pennyroyal, American and European, which are both considered perennials that produce lovely purplish flowers. Pennyroyal is a member of the mint family that acts as a natural pest defense and has historically been used in various types of medicines. The leaves and essential oils of this plant undoubtedly have some serious power, which means they can be dangerous if used incorrectly, so do not consume without consulting an expert first. Pennyroyal tends to also spread quite aggressively, so we suggest planting it in a pot if you don’t foresee yourself having time for some serious pruning!
American Pennyroyal a.k.a “false pennyroyal” is similar to the European variety in that it makes an excellent ground cover and emits a lovely, minty scent. To identify which type of pennyroyal you have growing, check out the number of stamens. If your plant has four stamens, it is European while the American variety will only have two.
Seed Depth: 1/2–1″
Space Between Plants: 6″
Space Between Rows: 12″
Germination Soil Temperature: 68–75°F
Days for Germination: 10–15
Sow Indoors: In late winter or early spring.
Sow Outdoors: In late spring when soil temperatures are warm and risk of hard frosts have passed.
Vegetative: Like most mint plants, they have a rather malleable root structure, so propagation can be achieved simply by ripping off a small piece of the plant with roots attached and planting in a container or garden soil.
Can be grown in containers anywhere as long as surrounding temperatures don’t dip below freezing and soil moisture is maintained. Native to Europe and Asia, pennyroyal thrives outdoors in USDA Zones 6–9: climates that exhibit warmer winter environments with only mild frosts and hot, slightly humid summers.
Natural: Full sun or partial shade.
Artificial: Will grow well under fluorescent lamps. Needs at least 10–12 hours daily, and up to 24 hours of light.
Soil: Prefers loamy soil with a balance between good drainage and soil moisture retention. Pennyroyal enjoys a neutral pH of 7.
Soilless: Can be grown in a variety of different mediums, including, but not limited to, rock wool, coco coir, and perlite mixtures.
Hydroponics: Thrives in hydroponics systems.
Aeroponics: Will thrive in aeroponic systems.
Water: Requires moderate levels of water. Be sure to keep soil moist but not saturated especially in the earlier stages of growth.
Nutrients: If planting in the ground, surround the bottom, top and sides of the hole with fresh potting soil: this will provide enough soil nutrients. Fertilize with compost once or twice per year.
Pruning: This plant can spread quickly, so clip back when it starts to become a bit bossy or unsightly.
Mulching: Fine pine or straw may be used to retain soil moisture in the earlier stages of growth.
Companions: Great companion to other veggies like cabbage and carrots due to its natural insecticidal properties.
Harvest: Trim sections of the plant by hand or with sharp scissors. Aim for leaving at least 1/3 of the plant with each harvest.
Storage: Placed in a dry dark cabinet in an airtight container, this herb can last up to an average of 6 months.
Fun Fact: Because of it’s lovely minty scent, pennyroyal was not only used in ancient cultures as a tea and to spice wine but also as a perfume! Considering how infrequently showers were to be had, we’re sure this herb was truly a god-send!
Preserve: Dry out freshly picked leaves by hanging upside down by their stems. Store in an airtight container.
Prepare: While traditionally pennyroyal leaves have been used in teas, we strongly recommend consulting your healthcare professional before consuming this herb. Note that pennyroyal oil should not be consumed under any circumstances.
Medicinal: A tea made from the foliage of this plant was often prescribed for colds and as a valuable digestive tonic; however, because it has a tendency to cause organ failure and sometimes death, please consult your local doctor to see if this tea is right for you.
Warnings: Pennyroyal essential oil can be extremely dangerous and should not be consumed under any circumstance. Because pennyroyal has been used historically as an abortifacient, pregnant women should not handle any form of this plant.