Herb · Lamiaceae
Shiso
Perilla frutescens
Pinch it often and shiso keeps handing you tender, fragrant leaves for pickles, garnishes, and wraps all summer long.
Full sun
Every 2–4 days
59–86°F · 15–30°C
70–90 days
Overview
Shiso belongs to the mint family, and like its cousins it is grown for fragrant leaves rather than showy flowers. It moves from seed to a leafy, knee-high plant in a single warm-season year, so even a first try gives you a full harvest. Cooks in Japan, Korea, and Vietnam lean on it constantly, tucking the leaves into food fresh, pickled, and wrapped.
You will find shiso in red, green, and ruffled bicolor forms, and each has a natural home in the kitchen. Red shiso lends its color and flavor to pickles, while the green kind is happiest fresh on the plate as a herb and garnish. The good news is that they all grow the same easy way, so there is no new routine to learn for each.
For all its easygoing nature, shiso has two habits worth keeping in mind, and both are simple to manage. It will bolt and turn bitter if the flowers are left alone, so picking often keeps the leaves sweet and tender. It also self-sows freely, and because the same plant is a proven poison to grazing cattle and horses, a little care about where you grow it goes a long way.
Care
The short version: give shiso full sun to a little shade, keep the soil evenly moist, and pinch it regularly so tender leaves keep coming and flowers never take charge.
Light
Shiso is happiest in full sun, though it takes partial shade in stride, which is a real help in hot places where harsh afternoon light can scorch the leaves. The deepest leaf color and the fullest aroma come when it gets plenty of light.
Water
Aim to keep the soil evenly moist but never soggy, which usually means watering every 2 to 4 days in warm weather. The leaves droop fast in dry heat, and a thirsty, stressed plant rushes to bolt, so steady watering protects both the leaves and your harvest.
Soil
Shiso settles in best in rich, well-drained loam with a good helping of organic matter mixed in. It prefers things a touch acidic, so a pH between 5.5 and 6.5 keeps it content.
Temperature
Shiso grows happily anywhere from 59°F to 86°F (15°C to 30°C) and truly comes alive in summer heat. It has no defense against frost, so there is no rush; wait for the cold to clear before setting plants out.
Humidity
Ordinary humidity in the 40% to 60% range keeps shiso comfortable, which is what most outdoor summers offer anyway. Gentle airflow around the leaves does more good than fussing over an exact reading.
Feeding
A light feeding once a month through spring and summer is all shiso asks, using a balanced fertilizer or a diluted liquid feed. Go easy on the nitrogen, since a heavy hand grows plenty of leaves that lose their lovely aroma.
Pruning
Pinch the growing tips often and shiso answers with bushier growth and a fresh flush of tender leaves. Snap off flower spikes as soon as you notice them to hold bolting at bay and keep the picking going.
Repotting
Because shiso is grown fresh from seed each year, it is not really a plant you repot. If a container plant shows circling roots, quick wilting, or early bolting, it has simply outgrown its pot and is ready to be replaced or moved up.
Size & spacing
Shiso grows to about 18 to 35 inches (45 to 90 cm) tall and spreads 12 to 18 inches (30 to 45 cm) across. Give each plant that much elbow room and air will move freely, keeping the leaves clean and healthy.
When to plant
Shiso loves warmth and cannot take a frost, so the timing is easy to get right. Start seeds indoors 6 to 8 weeks before your last frost, move the young plants outside once the cold has passed and the soil feels warm, then pick leaves all summer while you nip back any 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 of the little troubles with shiso show up right on the leaves, whether something has been nibbling or the plant is trying to flower and the leaves turn small and bitter. Spot them early and a gentle, quick response usually sets things right. Find your symptom below, then act while it still makes a difference.
Flower spikes rising while the leaves shrink and toughen
Your shiso is bolting, turning its attention from leaves to flowers as the days grow shorter or heat and stress nudge it along. The fresh leaves come in small, tough, and short on the flavor you want. Pinch the flower spikes out the moment they appear, pick more often to keep new growth coming, and sow a second batch so tender leaves are always within reach.
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 popping up far from where you sowed
Allowed to flower and set seed, shiso becomes a self-sowing wanderer that scatters volunteers across the garden and well beyond it. In parts of the country it has settled into pastures and woodland edges, so its spread reaches past your own beds. Cut the flower spikes before the seed ripens, pull the young volunteers while they lift out easily, and never compost or toss seeding plants where they could 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 scattered over the youngest leaves
Those little pits are the signature of flea beetles, tiny dark beetles that spring away the instant a hand comes near. They favor soft new growth, which is why the youngest leaves suffer most. Drape seedlings with a row cover until they firm up, tidy away nearby weeds, and keep the plants well fed and watered so they simply outgrow the nibbling.
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, chewed edges and silvery trails after a wet spell
This is the handiwork of slugs and snails, which feed after dark and leave leaf edges chewed into ragged scallops. The telltale sign is the ribbon of dried slime catching the light on leaves and soil by morning. Head out after dark to pick them off, pull back any heavy mulch at the base, and water a little less so the ground can dry between drinks.
Fix:
- Hand-pick at night
- Set out shallow traps and remove mulch harboring slugs
- Use iron-phosphate baits where appropriate
Toxicity
For people the leaves are a safe and cherished kitchen herb, so there is nothing to fear at the table. The plant is another matter for grazing animals: Perilla frutescens holds perilla ketone, a lung toxin that can bring on 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 and everyone stays safe.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds
Safe for
People
Cats Mild
A cat that nibbles a leaf might drool a little or feel briefly queasy, but anything serious is unlikely. Keep a gentle eye on a cat that chews the plant and set out fresh water.
Dogs Mild
A dog that chews a leaf may end up with a bit of drool or a soft stool that soon passes on its own. Guide a curious dog away from the plant and it should be perfectly fine.
Horses Toxic
A horse that grazes perilla can slide into severe respiratory distress, breathing fast and hard with an open mouth as fluid builds in the lungs. The harm comes on strongly and is often fatal, so keep horses well clear of the plant, above all once it flowers and seeds in late summer.
Rabbits Caution
Because perilla ketone is a lung toxin in grazing mammals, a rabbit nibbling the foliage is a genuine risk rather than a snack. Keep it off the menu and offer greens you already trust.
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 overwhelms their lungs. The threat is greatest in late summer while the plant is flowering and seeding, and the outcome is often fatal. Clear it from pastures and hay before animals can reach it.
Birds Caution
Cases involving birds are not well recorded, but the same lung toxin makes shiso a poor bet around poultry or pet birds. Keep them away from the foliage and seed heads just to be safe.
People Leaves safe
Shiso leaves are a beloved kitchen staple across East Asia, enjoyed fresh, pickled, and as a garnish, and they are safe for people. The toxin that troubles grazing animals is a pasture worry, not a problem 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 handful of distinct forms, and the one to grow simply 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 rich in anthocyanins, which is exactly why cooks turn to it to color and flavor pickles such as umeboshi.
Green shiso (aojiso)
The bright green flat leaves carry a gentler citrus-anise note and go straight onto the plate fresh, working as both a herb and a garnish.
Bicolor / ruffled (chirimen) types
These crinkled, two-toned leaves are green above and purple below, which earns them a welcome spot in the kitchen and the ornamental bed alike.
How to propagate
Shiso is a genuinely easy plant to raise from seed, and once it feels at home it will often sow the next generation for you, sometimes a bit more generously than you planned.
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 takes to seed with almost no fuss, whether you start it indoors 6 to 8 weeks before the last frost or sow it straight into warm soil in late spring. Press the seed gently onto the surface without covering it, since it needs light to sprout, and a cold spell beforehand gives it a helpful nudge. Allow 2 to 3 weeks for it to germinate and a few more to size up for picking, and once it is settled it will happily sow itself for years.
Myths
People eat shiso, so the whole plant must be harmless to every animal.
The leaves really are safe for cooking, yet Perilla frutescens carries perilla ketone, a documented cause of fatal lung poisoning in grazing cattle and horses. Safe on your plate does not mean safe in a pasture.
Shiso politely stays right where you plant it.
In truth it self-sows hard and has spread as an invasive weed across the southeastern and central United States, moving into pastures and woodlands. Cut the flower spikes before the seed sets and it stays comfortably in bounds.