How to Grow Pennyroyal
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Pennyroyal
Mentha pulegium
herbPennyroyal is a low-growing, aromatic mint with small, fragrant leaves and delicate purple or pink flowers. It spreads rapidly via runners and self-seeding, making it an excellent groundcover for moist areas. The plant has a strong, distinctive minty-camphoraceous aroma and has been used traditionally for centuries.
When should you plant Pennyroyal in your zone?
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Example Pennyroyal timeline · Pittsburgh, PA (Zone 6b)
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Plant Pennyroyal
Around Apr 17Near Pittsburgh's average last spring frost.
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Tend & protect
Late spring–summerWatering, feeding, and pest-watch reminders.
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Harvest Pennyroyal
Around May 17≈ 30 days after planting
Sample dates for Pittsburgh, PA. Sign up to get exact Pennyroyal dates for your own zip code.
Growing Conditions
Soil
Growing Zones
Find your zone →Thrives in zones 5-10; may survive zone 4 with winter protection
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Seedling
2-3 weeksTiny seedlings with 2-3 true leaves emerge 10-14 days after planting. Very delicate with minimal root system.
Keep soil consistently moist. Provide bottom heat (70-75°F) for faster germination. Thin to strongest seedlings if overcrowded.
Vegetative Growth
4-6 weeksPlant develops strong runners and dense foliage with characteristic small, oval-shaped leaves. Rapid horizontal and vertical growth occurs.
Pinch growing tips to encourage bushiness and prevent flowering. Water regularly. Begin harvesting leaves once plant is established. Fertilize monthly with balanced fertilizer.
Flowering
4-8 weeksDelicate purple, pink, or white flower spikes emerge from branch tips. Flowers attract pollinators and appear in mid to late summer.
Deadhead spent flowers to extend leaf production and prevent excessive self-seeding. Flowers are edible and attractive but reduce leaf quality.
Seed Production
3-4 weeksFlowers develop into small round seed pods. Plant may self-seed prolifically if flowers are left on plant.
Cut back before seed formation if you want to prevent aggressive spreading. Allow some flowers to set seed if you want more plants next year.
Dormancy/Winter
4-6 months depending on zoneIn cold climates, foliage dies back after first hard frost. Runners may survive underground in zones 5-6.
Mulch plants heavily in colder zones to protect roots. In zones 7+, plant may remain semi-evergreen. Prune back dead growth in spring.
Companion Planting
Plan your garden →Plant with:
Avoid planting near:
Common Pests
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Spray with water to dislodge, use insecticidal soap, ensure adequate humidity
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Remove by hand, spray with neem oil, use insecticidal soap, encourage beneficial insects
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Improve drainage, avoid overwatering, remove affected plants, sterilize tools
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Yellow sticky traps, neem oil spray, strong water spray, encourage parasitic wasps
Uses
Teas and beverages
CulinaryFresh or dried pennyroyal leaves make a distinctive minty tea with camphoraceous notes. Traditionally used in herbal tea blends, though should be used sparingly due to pulegone content. [source]
Traditional digestive and respiratory support
MedicinalHistorically used in small amounts for digestive complaints and respiratory support. Contains pulegone and menthol with traditional uses in folk medicine. [source]
Insect repellent
HouseholdStrong aroma repels fleas, mosquitoes, and other insects. Crushed leaves can be placed in areas to deter pests, and essential oil is sometimes used in natural insect preparations. [source]
Aromatic and fragrant uses
CraftDried flowers and leaves are attractive in potpourri, dried arrangements, and herbal crafts. The distinctive aroma adds character to craft projects. [source]
Pollinator attraction
WildlifeFlowers attract bees, butterflies, and other beneficial insects, making it valuable for pollinator gardens and supporting beneficial garden fauna. [source]
This is not medical advice. LizPlants is not a medical resource. Always consult a qualified healthcare professional before using plants medicinally.
Harvest Tips
Harvest leaves early morning after dew dries for maximum flavor and oil content. Pinch off top 3-4 inches of stems regularly to encourage bushiness. Cut stems back to 2-3 inches when harvesting larger quantities. For drying, harvest just before flowering when essential oil content peaks. Can harvest continuously throughout growing season.
Fun Facts
- 🌱 Pennyroyal's name derives from 'pulegium,' which comes from the Latin for 'flea' (pulex), as it was historically used to repel fleas from homes and animals.
- 🌱 The plant is famously mentioned in Shakespeare's plays and was a common herb in Elizabethan gardens, where it was used as a strewing herb on floors for its insect-repelling properties.
- 🌱 Pennyroyal is extremely vigorous and can become invasive in warm, moist climates; many gardeners now grow it exclusively in containers to prevent it from overtaking garden beds.
Gardening Terms
New to gardening? Learn about terms used in this guide:
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