Round-leaf mint bush Prostanthera rotundifolia
Round-leaf mint bush (Prostanthera rotundifolia) is an evergreen perennial shrub in the Lamiaceae family, native to South-eastern Australia and Tasmania. It grows 1–3 m (3.3–10 ft) tall and 1–2 m (3.3–6.6 ft) wide, wants part sun to part shade and moderate water, and is hardy to about -6 °C (21 °F). Space plants about 1.2 m (3.9 ft) apart.
Plan Round-leaf mint bush in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Round-leaf mint bush at a glance
| Type | Perennial shrub, evergreen |
|---|---|
| Family | Lamiaceae |
| Mature height | 1–3 m (3.3–10 ft) |
| Mature spread | 1–2 m (3.3–6.6 ft) |
| Spacing | 1.2 m (3.9 ft) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance none |
| Soil pH | 5–7 |
| Cold hardiness | About -6 °C (21 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 34 °C (93 °F) |
| Flowering | about 52–104 weeks after planting, for 4–6 weeks |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | South-eastern Australia and Tasmania |
| Common in gardens of | 🇦🇺 Australia, 🇬🇧 United Kingdom, 🇮🇪 Ireland, 🇳🇿 New Zealand, 🇺🇸 United States |
Is Round-leaf mint bush toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not known to be poisonous.
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 Round-leaf mint bush
No well-documented helpful pairing. Group it with plants that like part sun to part shade and moderate water.
Questions about Round-leaf mint bush
- How far apart should I plant Round-leaf mint bush?
- About 1.2 m (3.9 ft) apart, centre to centre. A mature plant spreads 1–2 m (3.3–6.6 ft).
- Does Round-leaf mint bush need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Round-leaf mint bush need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is Round-leaf mint bush?
- It tolerates about -6 °C (21 °F) once established, roughly USDA zone 9.
- When does Round-leaf mint bush flower?
- About 52–104 weeks after planting, for 4–6 weeks.
- Is Round-leaf mint bush poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not known to be poisonous.
- What grows well with Round-leaf mint bush?
- There is no well-documented companion pairing for Round-leaf mint bush. Group it with plants that like the same sun (part sun to part shade) and water (moderate).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- PlantNET: the NSW Flora Online, National Herbarium of New South Wales, Botanic Gardens of Sydney
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
Notes and assumptions
- An Australian native of poor, sandy soils: it wants sharp drainage and sun, and rots in heavy, wet ground or humid summers.
- Tiny, round, mint-scented leaves smothered for a few weeks in spring with mauve-purple, lipped flowers. Short-lived (5–10 years) and wants perfect drainage; tip-prune after flowering. Grown in mild British gardens and in conservatories.
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