Herb · Lamiaceae
Peppermint
Mentha × piperita
Give it steady moisture and a pot to call its own, and peppermint hands you fresh leaves all season.
Full sun
Every 2–4 days
80–90 days
USDA 3–8
Overview
Peppermint is a hardy perennial herb and a natural cross between watermint and spearmint. Its square stems, dark leaves, and cool menthol bite make it one of the most useful plants you can grow, whether you want fresh leaves for tea or a steady supply for the kitchen. It thrives in full sun to partial shade and shrugs off cold down to USDA zone 3.
What sets peppermint apart is how eagerly it grows. Give it rich, damp soil and it spreads by underground and surface runners, sending up new shoots in every direction. That vigor is a gift in a container and a headache in an open bed, so most gardeners keep it penned in from the start.
Because it's a sterile hybrid, peppermint won't come true from seed, so you start it from a division or a cutting instead. The upside is that it roots almost effortlessly. One healthy plant can fill a pot, edge a path, or supply a windowsill with very little fuss.
Care
The short version: full sun to part shade, soil kept evenly moist and never bone dry, and a pot or buried barrier to keep the runners in check.
Light
Peppermint does best in full sun but happily takes partial shade, which is welcome where summers run hot and dry. More sun means stronger flavor, while a little shade helps the soil hold the moisture it craves.
Water
Keep the soil consistently moist and never let it dry out, since peppermint wilts and loses flavor when thirsty. Plan on watering every 2 to 4 days, more often in containers or during hot, dry spells.
Soil
Give it rich, moisture-retentive loam with plenty of organic matter worked in. A pH between 6.0 and 7.0 suits it well, and soil that holds water without going waterlogged keeps the leaves coming.
Temperature
Peppermint is remarkably tough, surviving from -29°F to 84°F (-34°C to 29°C). It dies back in winter and returns from the roots each spring, which is what makes it so hardy across cold zones.
Humidity
Average humidity around 40% to 70% keeps the foliage lush. Good airflow matters more than the exact number, since stale, crowded air is what lets rust and mites take hold.
Feeding
Feed lightly through spring and summer with a balanced fertilizer or some compost or aged manure. Go easy on nitrogen, because too much grows soft leaves with weaker oils and less of the flavor you're after.
Pruning
Pinch and harvest the stem tips often to keep the plant bushy rather than leggy. Cut off the flower spikes to keep the leaves tasty, and shear the whole plant back hard after it blooms to bring on fresh growth.
Repotting
Peppermint fills a pot fast, so repot it every 1 to 2 years, or sooner if roots circle the container, leaves shrink, or runners push out the drainage holes. Divide it as you go to keep it vigorous.
Size & spacing
Plants reach 12 to 35 inches (30 to 90 cm) tall and spread 1.5 to 4 feet (45 to 120 cm) wide by runner. Give each one room, or better yet a pot, so the spread stays under control.
When to plant
Peppermint is tough and cold-hardy, so timing is relaxed compared with tender crops. Set out divisions or rooted cuttings in spring once the last frost has passed, then pick leaves right through the growing season, pinching off the flower spikes as they form to keep the foliage at its best.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring, after the last frost, from divisions of runners or rooted stem cuttings
- Harvest: Harvest leaves throughout the growing season; pinch off flower spikes (summer bloom) to maintain leaf quality
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
Peppermint is easygoing, so most of its problems come down to wet, crowded growth or its own runaway spread. Catch the early signs on the leaves or at the edges of the bed and you can step in before things get away from you. Match what you see below, then act while it still helps.
Stems wilting and dying back on one side
Verticillium wilt lives in the soil and clogs the plant's plumbing from the inside, so the damage often shows on just one side and worsens as the weather warms. Cut a wilting stem and you'll find brown streaking in the tissue. There's no cure once it takes hold, so pull and destroy the plant, then start fresh stock in clean, uninfested soil and don't replant mint where it has struck before.
Fix:
- Remove and destroy affected plants
- Do not replant mint or other susceptible crops in the same soil
- Plant resistant mint stock in fresh, uninfested soil
Orange-brown powdery spots under the leaves
This is mint rust, a fungus that thrives where the leaves stay wet and crowded. Pull off the spotted foliage the moment you see those raised pustules, thin the stems so air can move through, and water at the base instead of over the top. In a bad year, cut the whole stand to the ground and clear away the debris.
Fix:
- Remove and destroy infected foliage immediately
- Improve air circulation by thinning crowded stems
- Avoid overhead watering and wetting foliage
- Cut affected plants to the ground and dispose of debris in severe cases
Mint taking over the bed and crowding its neighbors
This is runner spread, and it's simply what peppermint does. Underground and surface runners radiate from the parent plant and send up new shoots wherever they land, so a polite clump becomes a takeover in a season or two. The fix is containment: grow it in a pot or a buried bottomless container, dig out any escapees as you spot them, and edge the bed deeply so the runners hit a wall.
Fix:
- Grow in containers or buried barriers to confine roots
- Regularly dig out and remove escaped runners
- Edge beds deeply and monitor margins each season
Old clump going woody in the middle with smaller leaves
An aging stand turns into a congested, woody clump that loses steam, with a bare or tired center ringed by matted runners. Lift it and the tangle is obvious. Every 2 to 3 years, divide it: throw out the woody heart, replant the vigorous outer pieces, and work some compost into the fresh soil to set them up again.
Fix:
- Divide the clump every 2-3 years
- Discard old woody center and replant vigorous outer divisions
- Refresh soil with compost at replanting
Dusty, stippled leaves with fine webbing
Hot, dry, dusty air invites spider mites, and they leave a tell-tale speckling with thin webbing under the leaves. Tap a leaf over white paper and you'll see the tiny mites move. Blast them off with a strong jet of water, treat the undersides with insecticidal soap or horticultural oil, and keep the plant well watered so the conditions they love never set in.
Fix:
- Spray foliage with a strong jet of water to dislodge mites
- Apply insecticidal soap or horticultural oil to undersides of leaves
- Increase humidity and keep plants well watered
Toxicity
Peppermint is a culinary herb, so the leaves are perfectly safe for people to eat and brew. For pets it's a different story: the essential oils make it a mild hazard to cats, dogs, and horses, bringing on vomiting or diarrhea if they eat much, and concentrated peppermint oil is far more dangerous than the plant itself. Keep grazing animals away from large stands and keep the oil away from cats entirely.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
A nibble of leaf usually passes, but a real mouthful can bring on vomiting and diarrhea from the essential oils. Cats are the most sensitive here, since they lack the liver enzymes to break those oils down, so the bigger danger by far is concentrated peppermint oil. Keep that away from them entirely.
Dogs Mild
A few leaves rarely cause trouble, but a dog that grazes on a whole plant can end up with vomiting and diarrhea. Watch for drooling or a poor appetite, and keep concentrated oils out of reach.
Horses Mild
Small amounts in pasture are generally shrugged off, though a horse that eats it in quantity may get an upset stomach and loose droppings from the oils. Steer them away from large stands.
Rabbits Mild
The same minty oils that bother cats and dogs can unsettle a rabbit's sensitive gut, so this isn't a free-choice green. Offer only a leaf or two now and then and watch for any soft stool.
Livestock Mild
Goats, sheep, and cattle can browse a little without harm, but a big helping of the aromatic foliage may bring on digestive upset. Treat it as an occasional taste rather than fodder.
Birds Caution
There's little hard data on mint and pet birds, and the potent oils are reason enough to be careful. Skip it as a regular green and keep any essential oil well clear of the cage.
People Safe
Peppermint is a culinary herb, and the leaves are good to eat fresh, dried, or steeped as tea. The only real caution is the concentrated essential oil, which is far stronger than the plant and not for casual use.
Concentrated peppermint essential oil is a significantly greater hazard, especially to cats, which lack the liver enzymes to metabolize it; keep essential oils away from pets.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
Peppermint comes in a few named types that differ mostly in color and the strength of their menthol. These are the ones worth knowing.
Chocolate mint
Its dark-tinged stems and leaves carry a warm chocolate-peppermint scent that makes it a favorite for desserts and tea.
Black peppermint
Purple-tinged stems and dark foliage mark out this strong, high-menthol type prized for its bold flavor.
White peppermint
Greener stems and paler leaves give this one a milder, sweeter taste than its darker cousins.
How to propagate
Peppermint won't grow true from seed, but it's one of the easiest plants to clone, whether you split a clump or root a few cuttings in a glass of water.
DivisionEasy
Spring or early autumn · 2 to 4 weeks
Division is the surest way to make more peppermint, since the sterile hybrid won't grow true from seed. In spring or early autumn, lift the clump and pull it apart into sections of rooted runner, then replant those pieces. They settle in and start growing within 2 to 4 weeks.
Stem cuttingsEasy
Spring through summer · 1 to 3 weeks
Cuttings are just as easy and give you copies that are true to the parent, which matters with a sterile hybrid like this. Take 10 to 15 cm stems anytime from spring through summer and stand them in water or moist mix. Roots appear in 1 to 3 weeks, and the new plant is ready to pot on.
Myths
You can grow true peppermint from seed.
Peppermint is a sterile hybrid of watermint and spearmint, so it sets little or no viable seed and any seedlings you do get won't be true peppermint. The only way to keep the plant true is to propagate it vegetatively, by dividing the clump or rooting cuttings.
Mint is harmless to pets because people cook with it.
Safe in your kitchen doesn't mean safe in a pet's stomach. The ASPCA lists mint as toxic to cats, dogs, and horses, where the essential oils cause vomiting and diarrhea, and concentrated peppermint oil is far more dangerous, especially to cats that can't break it down.