Herb · Lamiaceae
Shiso
Perilla frutescens
Pinch it often for tender, fragrant leaves all summer, and it pays you back in pickles, garnishes, and wraps.
Full sun
Every 2–4 days
59–86°F · 15–30°C
70–90 days
Overview
Shiso is a fast-growing member of the mint family grown for its fragrant leaves rather than its flowers. It runs through its whole life in a single season as a warm-season annual, sizing up from seed to a leafy, knee-high plant by midsummer. Cooks across Japan, Korea, and Vietnam reach for it constantly, where it shows up fresh, pickled, and wrapped around all manner of food.
The plant comes in red, green, and ruffled bicolor forms, each with its own job in the kitchen. Red shiso colors and flavors pickles, while the green type goes onto the plate fresh as a herb and garnish. All of them grow the same way and respond to the same simple care.
Easy as it is, shiso has two habits worth respecting. It bolts and turns bitter if you let it flower, so steady harvest keeps the leaves coming, and it self-sows hard enough to escape the garden. The same plant that feeds your kitchen is also a documented poison to grazing cattle and horses, so where you grow it matters.
Care
The short version: full sun to light shade, soil kept evenly moist, and regular pinching to keep tender leaves coming and flowers from taking over.
Light
Shiso does best in full sun but takes partial shade without much complaint, which helps in hot regions where afternoon glare scorches the leaves. The richest leaf color and aroma come with plenty of light.
Water
Keep the soil evenly moist but never waterlogged, watering every 2 to 4 days in warm weather. The leaves wilt fast in dry heat, and drought stress pushes the plant to bolt early, which cuts your leaf quality short.
Soil
Plant in rich, well-drained loam with plenty of organic matter worked in. A pH between 5.5 and 6.5 suits it best, on the slightly acidic side.
Temperature
Shiso grows happily from 59°F to 86°F (15°C to 30°C) and thrives in summer heat. It has no tolerance for frost, so wait until the cold is gone before setting plants out.
Humidity
Average humidity around 40% to 60% keeps the plant comfortable, matching most outdoor summers. Good airflow around the leaves matters more than chasing an exact number.
Feeding
Feed monthly through spring and summer with a balanced fertilizer or a diluted liquid feed. Go easy on the nitrogen, since too much grows lush leaves that lose their aroma.
Pruning
Pinch the growing tips often to push out bushy branching and a flush of tender new leaves. Snap off flower spikes the moment they appear to hold off bolting and keep the harvest going.
Repotting
Shiso is grown fresh from seed each year, so it isn't really repotted. Roots circling the pot, fast wilting, or early bolting are signs a container plant has run out of room and is ready to be replaced or moved up.
Size & spacing
Plants reach 18 to 35 inches (45 to 90 cm) tall with a spread of 12 to 18 inches (30 to 45 cm). Give each one that much room so air moves freely and the leaves stay clean.
When to plant
Shiso needs warmth and won't tolerate frost. Start the seeds indoors 6 to 8 weeks before your last frost, move the plants out once the cold has passed and the soil has warmed, then harvest leaves all summer while you pinch back flower spikes to stretch the season.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 6 to 8 weeks before the last spring frost; surface-sow and do not cover, as seed needs light to germinate
- Plant: After all danger of frost has passed and soil has warmed in late spring
- Harvest: Harvest leaves through summer once plants are established; pinch flower spikes to prolong harvest. Late-summer flowering and seeding is when perilla-ketone concentration and livestock-poisoning risk peak.
Hardiness
USDA hardiness zones: 2–11
Temperature: down to -46°C
Troubleshooting
Most shiso trouble shows up on the leaves, either chewed by pests or going small and bitter as the plant tries to flower. Catch these early and a quick response keeps the harvest going. Match what you see below, then act while it still helps.
Flower spikes rising as the leaves shrink and toughen
Shiso is bolting, shifting its energy from leaves to flowers once the days shorten or heat and stress push it along. The new leaves come in small, tough, and short on flavor. Pinch out the flower spikes the moment they show, harvest more often to keep fresh growth coming, and sow a second batch so you always have tender leaves on hand.
Fix:
- Pinch out flower spikes as soon as they appear
- Harvest leaves more frequently to encourage vegetative growth
- Make successional sowings for a continuous supply of tender leaves
Volunteer seedlings springing up far from where you planted
Left to flower and set seed, shiso turns into a self-sowing weed that drops volunteers across the garden and well past its edges. It has naturalized into pastures and woodland edges in parts of the country, so the spread matters beyond your own beds. Cut the flower spikes before the seed ripens, pull young volunteers while they're easy, and never compost or dump seeding plants where they can take hold in the wild.
Fix:
- Remove flower spikes before seed set
- Pull volunteer seedlings while young
- Do not compost or dump seeding plants where they can naturalize
Tiny shot-hole pits peppering the young leaves
This is flea beetle damage, the work of small dark beetles that hop away the moment you reach for them. They go after tender new growth, so the youngest leaves take the worst of it. Cover seedlings with a row cover until they toughen up, clear out weeds nearby, and keep the plants growing strong so they outpace the chewing.
Fix:
- Cover young plants with floating row cover until established
- Remove nearby weed hosts
- Apply an approved insecticidal product only if damage is severe and the crop is not being harvested for food within the label interval
Ragged holes and silvery slime trails after wet weather
Slugs and snails feed at night and leave the edges of the leaves chewed into ragged scallops. The giveaway is the trail of dried mucus glinting on the foliage and soil come morning. Go out after dark to pick them off, thin back any heavy mulch around the base, and ease up on the water so the ground dries between drinks.
Fix:
- Hand-pick at night
- Set out shallow traps and remove mulch harboring slugs
- Use iron-phosphate baits where appropriate
Toxicity
The leaves are a safe and beloved kitchen herb for people, but the plant is a different story for grazing animals. Perilla frutescens contains perilla ketone, a lung toxin that causes severe, often fatal breathing trouble in horses and cattle that eat it, with the danger highest in late summer. Keep it well away from pastures, hay, and grazing animals.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
A cat that nibbles a leaf might drool a little or have a brief upset stomach, but anything serious is unlikely. Keep an eye on a cat that chews on the plant and offer fresh water.
Dogs Mild
Chewing a leaf may leave a dog with a touch of drool or a loose stool that passes on its own. Steer a curious dog away from the plant and it should be fine.
Horses Toxic
A horse that grazes perilla can fall into severe respiratory distress, with fast, labored, open-mouthed breathing as the lungs fill with fluid. The damage strikes hard and is often fatal, so keep horses well clear of the plant, especially once it flowers and seeds in late summer.
Rabbits Caution
Perilla ketone is a lung toxin in grazing mammals, so a rabbit nibbling the foliage is a real risk rather than a treat. Leave it off the menu and stick to greens you know are safe.
Livestock Severe
Cattle, goats, and sheep that graze perilla mint can develop acute respiratory distress, open-mouthed panting, and atypical interstitial pneumonia as the perilla ketone floods their lungs. The danger peaks in late summer when the plant is flowering and seeding, and the outcome is frequently fatal. Pull it from pastures and hay before animals can reach it.
Birds Caution
Bird-specific cases aren't well documented, but the same lung toxin makes this a poor choice around poultry or pet birds. Keep them away from the foliage and seed heads to be safe.
People Leaves safe
Shiso leaves are a kitchen staple across East Asia, eaten fresh, pickled, and as a garnish, and they're safe for people. The toxin that harms grazing animals is the concern in pastures, not on your plate.
Safe to handle and harvest for cooking; the concern is ingestion by grazing livestock, not skin contact.
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
Shiso comes in a few distinct forms, and which one you grow depends on whether you want color for the pickle jar or fresh leaves for the plate.
Red/Purple shiso (akajiso)
Its deep red-purple leaves are loaded with anthocyanins, which is why cooks reach for it to color and flavor pickles like umeboshi.
Green shiso (aojiso)
The bright green flat leaves carry a milder citrus-anise note and go straight onto the plate fresh, as a herb and a garnish.
Bicolor / ruffled (chirimen) types
These crinkled, two-toned leaves run green on top and purple beneath, earning them a place in the kitchen and the ornamental bed alike.
How to propagate
Shiso is simple to grow from seed, and once it settles in it tends to sow the next generation for you, sometimes more than you bargained for.
SeedEasy
Start indoors 6 to 8 weeks before last frost, or direct-sow after the soil warms in late spring · 2 to 3 weeks to germinate and several more weeks to reach harvestable size
Shiso grows readily from seed, started indoors 6 to 8 weeks before the last frost or sown straight into warm soil in late spring. Press the seed onto the surface without covering it, since it needs light to sprout, and a spell of cold beforehand helps it along. Give it 2 to 3 weeks to germinate and a few more to size up for harvest, and once it settles in it sows itself for years to come.
Myths
Because people eat shiso, the whole plant must be harmless to every animal.
The leaves are safe for the kitchen, but Perilla frutescens carries perilla ketone, a documented cause of fatal lung poisoning in grazing cattle and horses. What is safe on your plate is not safe in a pasture.
Shiso stays put where you plant it.
It self-sows hard and has naturalized as an invasive weed across the southeastern and central United States, pushing into pastures and woodlands. Cut the flower spikes before the seed sets if you want to keep it in bounds.