Herb · Lamiaceae
Mint
Mentha spicata
Give it steady moisture and a pot of its own, and mint pushes out fresh green leaves from spring to frost.
Partial shade
Every 2–4 days
59–77°F · 15–25°C
80–90 days
Overview
Mint shows its family at a glance. Run a stem between your fingers and you feel the flat sides of the square stalk that marks the Lamiaceae, the same build basil and sage carry, and the kind most gardens hold is spearmint. Its leaves come to a clean point in a bright, clear green, and pinching one loose sends up the cool, sweet scent that names the plant on the spot.
The plant grows outward as much as up. From the base it drives out runners, pale creeping stems that travel over and just under the soil, rooting at each node to raise a fresh green sprig, so one plant threads a whole bed in a season. That relentless push of new growth makes mint almost impossible to kill, and it is why gardeners hold it in a pot or a sunken, bottomless container instead of open ground.
The leaves keep coming year on year. Mint is a hardy perennial that dies back and returns in cool and mild climates, shrugging off neglect, and a handful of its bright tops flavors tea, salads, and summer drinks. Kept in damp soil under a little shade, the plant hardly pauses.
Care
The short version: mint wants part shade and rich, evenly moist soil, a pinch through the season to hold its bushy green shape, and a container or edged bed to keep the pale runners in check.
Light
Mint holds its best green in partial shade, especially where summers run hot, though it takes full sun as long as the soil stays moist. Morning light with a stretch of afternoon cover gives the tenderest, fullest-flavored leaves.
Water
Keep the soil consistently moist and never let the root zone dry, since the leaves go limp fast once the plant runs thirsty. In warm weather or a pot that means a drink every 2 to 4 days, more the moment the foliage starts to sag.
Soil
Root it in rich, moist, well-draining loam worked full of organic matter. A pH of 6.0 to 7.0 suits it, and that spans most ordinary garden soil.
Temperature
The leaves grow lush and tender between 59°F and 77°F (15°C to 25°C), the cool-to-mild range mint came from. It endures heat with enough water but slows down and toughens its foliage once the air turns too warm.
Humidity
Average humidity of 40% to 70% keeps the leaves supple, and outdoor air usually sits in that band. Dry indoor air draws spider mites onto the foliage, so a contained pot benefits from a little added moisture nearby.
Feeding
Mint asks for barely any feeding. A balanced all-purpose fertilizer or a light top-dressing of compost in spring carries the leaves through the season, and overfeeding only dulls their flavor.
Pruning
Pinch the growing tips often to hold the plant bushy and to take leaves as you go. Snip off the flower spikes as they rise so the leaves keep their sharpest taste, and cut the plant back hard after it flowers to draw out fresh tender shoots.
Repotting
A potted mint knits itself full of roots and runners fast, so divide and repot it once a year or whenever the container packs tight. Drop the woody center, keep the vigorous outer growth, and start it in fresh soil.
Size & spacing
Mint stands 12 to 35 inches (30 to 90 cm) tall on its leafy square stems and spreads 2 to 4 feet (60 to 120 cm) across, wider still where the runners run free. Give it real room, or a container, so the sprawling growth does not crowd its neighbors.
When to plant
Mint shrugs off cold once its shoots are up, but young plants want a settled spring. Start seed indoors 6 to 8 weeks before the last frost, set the plants out after the hard frosts pass, then strip leaves from the stems right through the growing season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6-8 weeks before last spring frost
- Plant: Spring, after danger of hard frost has passed
- Harvest: Harvest leaves throughout the growing season; pinch off flower spikes for the best leaf flavor
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
Mint is tough, so most of its troubles read straight off the leaves and stems: foliage held wet, a hot dry spell that fades the green, or runners carrying the plant past its space. Match what you see below and act early, while a quick fix still holds.
Orange-brown pustules on the leaf undersides
Turn a leaf over and the raised orange-to-brown specks powdering its underside are mint rust, a fungus that settles in where the foliage stays wet and the air hangs still. Pick off every spotted leaf and bin it rather than compost it, thin the stems so the leaves dry faster, and pour water at the soil instead of over the top. When the pustules cover a plant, cutting it to the ground and clearing the litter wipes the slate clean.
Fix:
- Remove and destroy infected foliage (do not compost)
- Improve air circulation by thinning growth
- Avoid overhead watering and keep foliage dry
- Cut affected plants to the ground and dispose of debris in severe cases
Mint sending shoots far past its clump
New sprigs of bright green mint keep surfacing well beyond the parent clump, each one riding a pale horizontal stem. These are the underground and surface runners, and they will thread a whole bed within a season. Follow a stray shoot back along its runner to the soil and dig the length out, then sink the plant into a bottomless pot or a deeply edged bed so the runners strike a wall.
Fix:
- Dig out and sever stray runners
- Grow mint in a sunken bottomless pot or contained bed to restrict spread
- Edge the planting deeply to block runner travel
Potted mint fading, its leaves shrinking
The once-full leaves come in smaller and paler, and the soil bakes dry within hours; a pot of mint knits itself into a rootbound ball faster than nearly any herb. Slide the plant out and a dense mat of white roots and runners spirals around the shape of the pot. Split that clump apart, throw out the tough woody heart, and settle the fresh outer pieces into new soil.
Fix:
- Divide the clump and replant divisions
- Repot into fresh soil in a larger container
- Discard the woody center and keep vigorous outer growth
Speckled, dusty leaves with faint webbing
The bright green leaves lose their color to a fine yellow speckling, and a faint webbing threads the undersides; that is the mark of spider mites working in hot, dry air. Tap a leaf over a sheet of white paper and the specks that fall and crawl give them away. Blast the foliage with a hard jet of water, hold the soil moist and the surrounding air humid, and turn to insecticidal soap only when they cling on.
Fix:
- Spray foliage with a strong jet of water to dislodge mites
- Increase humidity and keep soil evenly moist
- Apply insecticidal soap if infestation persists
Toxicity
The bright green leaves are a kitchen herb people eat freely, and the plant poses little danger to animals. Its essential oils can give a pet a mild stomach upset if it grazes a large mouthful, so keep grazing in check. The one real warning is pennyroyal, a poisonous relative you should never confuse with garden mint or grow around animals.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
A single torn leaf does no harm, but a cat that shears off a mouthful of the green tops may drool and bring the wad back up. The essential oils in the leaf are the irritant, so the upset stays mild and passes once the plant is out of reach.
Dogs Mild
Most dogs press a nose to the fragrant leaves and turn away. One that bites through a leafy patch can end up with an upset stomach, vomiting or loose stools, that usually clears on its own.
Horses Mild
A horse would need to crop a whole mouthful of the leafy stems before the oils told on it. When that happens the signs are mild colic and loose droppings rather than anything grave.
Rabbits Mild
A leaf or two sits fine, but the oil-rich foliage can leave a rabbit gassy and loose if it clears a pile of it. Keep mint to the odd small sprig.
Livestock Mild
Goats, sheep, and cattle mostly pass the pungent leaves by. One that does chew through a stand may show some digestive upset, though it stays minor.
Birds Caution
Firm data on birds and the aromatic leaves is thin, so lean cautious. Offer just a small leaf now and then and leave concentrated mint oil out completely.
People Safe
The bright green leaves are a kitchen herb, eaten fresh and dried and steeped into tea with no trouble at all. The lone caveat is the lookalike pennyroyal, which is genuinely poisonous, so the two must never be confused.
Common garden mint (Mentha spicata) causes only mild GI signs, but its dangerous relative pennyroyal (Mentha pulegium) contains high levels of pulegone and is seriously toxic, capable of causing liver damage in pets and people; do not confuse or substitute the two.
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
Dozens of mints exist, but a few carry most of the work between the pot and the garden. These are the ones worth telling apart by leaf and flavor.
Spearmint (Mentha spicata)
Spearmint carries pointed leaves of a bright, clear green over a sweet, mild flavor, the culinary standard for both the pot and the cold glass.
Peppermint (Mentha × piperita)
Peppermint, a natural cross of spearmint and water mint, packs far more menthol into its leaves and reads sharper and cooler on the tongue.
'Kentucky Colonel' Spearmint
This spearmint selection unfurls notably large leaves, the ones bartenders reach for first when muddling a mint julep.
How to propagate
Mint all but copies itself, so one plant hands you every start you need. Take cuttings from the stems or split a clump rather than sowing seed, since seed-grown mint rarely carries the parent's flavor.
DivisionEasy
Spring or early fall · 2 to 4 weeks
Division holds a named mint true to type. In spring or early fall, lift a settled clump and tease it into pieces that each keep a tangle of white roots and pale runners, then set them back in the soil. Watered in, the divisions take hold within 2 to 4 weeks and start unfurling fresh green shoots.
Stem cuttingsEasy
Spring through summer · 1 to 2 weeks to root
Cuttings root with little trouble from spring through summer. Snip 10 to 15 cm (4 to 6 inch) tips off the square stems and stand them in water or press them into moist soil, and pale roots break from the lower nodes in 1 to 2 weeks. Skip seed, which sprouts unevenly and rarely carries the parent's flavor true.
Myths
Every kind of mint is dangerously poisonous to pets and should never grow near animals.
The bright, fragrant leaves earn only a mild rating from the ASPCA, and a grazing pet gets nothing worse than a passing stomach upset. The true hazard is the relative pennyroyal, whose pulegone can damage the liver. Ordinary spearmint is safe to grow, while pennyroyal is kept well clear of animals.
Mint is a tidy, well-behaved herb you can drop in anywhere in the garden.
Those innocent-looking green tops ride runners above and below the soil and blanket a bed in a single season. A buried bottomless pot or a sharply edged bed holds the plant in place, but loose in open ground its runners return for years.