Pennyroyal Mentha pulegium
Pennyroyal (Mentha pulegium) is an evergreen perennial herb in the Lamiaceae family, native to Europe, North Africa and western Asia (damp grassland). It grows 10–40 cm (4–16 in) tall and 30–60 cm (12–24 in) wide, wants full sun and high water, and is hardy to about -15 °C (5 °F). Space plants about 30 cm (12 in) apart.
Plan Pennyroyal in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Pennyroyal at a glance
| Type | Perennial herb, evergreen |
|---|---|
| Family | Lamiaceae |
| Mature height | 10–40 cm (4–16 in) |
| Mature spread | 30–60 cm (12–24 in) |
| Spacing | 30 cm (12 in) centre to centre |
| Sun | Full sun, at least 4 h of direct sun a day |
| Water | High; drought tolerance none, waterlogging tolerance moderate |
| Soil pH | 6–7.5 |
| Cold hardiness | About -15 °C (5 °F) once established (roughly USDA zone 7) |
| Heat stress | Likely above about 32 °C (90 °F) |
| Flowering | from about July for 6–11 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Europe, North Africa and western Asia (damp grassland) |
| Common in gardens of | 🇬🇧 United Kingdom, 🇪🇸 Spain, 🇵🇹 Portugal, 🇫🇷 France, 🇮🇹 Italy, 🇬🇷 Greece, 🇲🇦 Morocco, 🇺🇸 United States, 🇦🇺 Australia |
| Invasive in | California (Cal-IPC), south-eastern Australia, New Zealand: check local rules before planting |
Is Pennyroyal toxic?
- People: severely toxic
- Cats: moderately toxic
- Dogs: moderately toxic
- Parts: essential oil, leaves in quantity
Pennyroyal oil (pulegone) has killed people who took it by mouth and is listed by the ASPCA as toxic to cats and dogs (liver failure). The fresh plant in the garden is only a risk if eaten in quantity.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Pennyroyal
No well-documented helpful pairing. Group it with plants that like full sun and high water.
Questions about Pennyroyal
- How far apart should I plant Pennyroyal?
- About 30 cm (12 in) apart, centre to centre. A mature plant spreads 30–60 cm (12–24 in).
- Does Pennyroyal need full sun?
- Full sun: at least 4 hours of direct sun a day.
- How much water does Pennyroyal need?
- High water. Drought tolerance is none and waterlogging tolerance moderate.
- How cold-hardy is Pennyroyal?
- It tolerates about -15 °C (5 °F) once established, roughly USDA zone 7.
- When does Pennyroyal flower?
- From about July for 6–11 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Pennyroyal poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs moderately toxic; for people severely toxic. Pennyroyal oil (pulegone) has killed people who took it by mouth and is listed by the ASPCA as toxic to cats and dogs (liver failure). The fresh plant in the garden is only a risk if eaten in quantity.
- What grows well with Pennyroyal?
- There is no well-documented companion pairing for Pennyroyal. Group it with plants that like the same sun (full sun) and water (high).
Sources and evidence
Evidence grade B (B: extension service or peer-reviewed).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- CABI Invasive Species Compendium, CABI
- Poisonous plants of North Carolina / Plant Toolbox toxicity, NC State Extension
Notes and assumptions
- A low, creeping mint with lilac whorls; once strewn and used against fleas (Latin pulex), a use recorded by Pliny. Grown today as a fragrant lawn or path edging plant, not for eating.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Basil Ocimum basilicum
- Rosemary Salvia rosmarinus
- Thyme Thymus vulgaris
- Mint Mentha spicata
- English lavender Lavandula angustifolia
- Creeping thyme Thymus serpyllum
- Common sage Salvia officinalis
- Oregano Origanum vulgare