Herb · Lamiaceae
Shiso
Perilla frutescens
Keep pinching and shiso keeps pumping out tender, fragrant leaves for pickles, garnishes, and wraps all summer.
Full sun
Every 2–4 days
59–86°F · 15–30°C
70–90 days
Overview
Shiso is a member of the mint family grown for its fragrant leaves, and it moves fast. As a warm-season annual it races from seed to a leafy, knee-high plant in a single season, ready to pick by midsummer. Cooks across Japan, Korea, and Vietnam grab it constantly, working the leaves in fresh, pickled, and wrapped around food.
Half the fun is the range, since shiso comes in red, green, and ruffled bicolor forms, each pulling its weight in the kitchen. Red shiso drives the color and flavor in pickles, and the green kind lands fresh on the plate as a herb and garnish. Best part, they all grow the same easy way, so there is nothing new to learn when you add another.
Two habits keep shiso interesting to grow. Let it flower and it will bolt and turn bitter, so keep harvesting and it keeps handing you tender leaves. It also self-sows hard enough to jump the garden fence, and since the same plant is a proven poison to grazing cattle and horses, picking the right spot for it matters.
Care
The short version: give it full sun to light shade, keep the soil evenly moist, and pinch it often to keep tender leaves coming and flowers on the back foot.
Light
Shiso powers up in full sun and still does well in partial shade, which comes in handy in hot spots where afternoon glare would scorch the leaves. Load it up with light and the leaf color and aroma come in strongest.
Water
Keep the soil evenly moist but never waterlogged, which usually means a drink every 2 to 4 days in warm weather. The leaves wilt fast in dry heat, and a stressed, thirsty plant bolts early and cuts your leaf quality short, so stay on top of the water.
Soil
Plant shiso in rich, well-drained loam loaded with organic matter and it will run. It leans slightly acidic, so hold the pH between 5.5 and 6.5 to keep it moving.
Temperature
Shiso thrives anywhere from 59°F to 86°F (15°C to 30°C) and really hits its stride in summer heat. Frost stops it cold, so wait out the last of the cold before you set plants out.
Humidity
Everyday humidity around 40% to 60% keeps shiso cruising, which is what most outdoor summers already deliver. Good airflow around the leaves counts for far more than chasing an exact number.
Feeding
Feed monthly through spring and summer with a balanced fertilizer or a diluted liquid feed to keep the leaves flowing. Ease off the nitrogen, though, since piling it on grows soft leaves that lose their aroma.
Pruning
Pinch the growing tips often and shiso answers with bushier growth and a fresh rush of tender leaves. Snap off flower spikes the second they show to stall bolting and keep the harvest going strong.
Repotting
You grow shiso fresh from seed each year, so repotting rarely comes up. Watch for circling roots, fast wilting, or early bolting, which flag a container plant that has run out of room and needs replacing or a bigger pot.
Size & spacing
Shiso shoots up to 18 to 35 inches (45 to 90 cm) tall and spreads 12 to 18 inches (30 to 45 cm) wide. Give each plant that much room so air keeps moving and the leaves stay clean.
When to plant
Shiso runs on warmth and folds at the first frost, so time it right and it takes off. Start seeds indoors 6 to 8 weeks before your last frost, get plants outside once the cold clears and the soil warms, then harvest all summer while you pinch off flower spikes to keep the run going.
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
Almost every shiso hiccup lands on the leaves, whether pests are chewing them or the plant is bolting and the leaves turn small and bitter. Jump on it early and a quick move keeps the harvest rolling. Match what you see below, then act while it still turns things around.
Flower spikes shooting up as the leaves shrink and toughen
Shiso has hit bolting, swinging its energy from leaves to flowers as the days shorten or heat and stress kick in. The new leaves come in small, tough, and short on flavor. Pinch out the flower spikes the moment they show, harvest more often to drive fresh growth, and start a second sowing so tender leaves never dry up.
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 past where you sowed
Let it flower and set seed and shiso turns into a self-sowing weed, flinging volunteers across the garden and way past its edges. It has naturalized into pastures and woodland edges in parts of the country, so the spread runs well beyond your own beds. Cut the flower spikes before the seed ripens, pull young volunteers while they lift out 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 fresh new leaves
That peppering is flea beetles, small dark beetles that spring off the instant you lean in. They chase soft new growth, so the youngest leaves take the hits first. Throw a row cover over seedlings until they toughen up, clear the weeds nearby, and push strong growth so the plants simply outrun 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 chewed edges and shiny trails after wet weather
You have got slugs and snails, night feeders that chew the leaf edges into ragged scallops. The dried slime trails glinting on leaves and soil at dawn give them away. Head out after dark and pick them off, strip back heavy mulch at the base, and dial back 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
For people, shiso leaves are a safe, much-loved kitchen herb, so cook away with confidence. Grazing animals are the flip side: Perilla frutescens packs perilla ketone, a lung toxin that triggers severe, often fatal breathing trouble in horses and cattle that eat it, and it peaks in late summer. Keep it well clear of 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 bit or get a short-lived upset stomach, but serious trouble is unlikely. Keep tabs on a cat that chews the plant and set out fresh water.
Dogs Mild
A dog that chews a leaf may drool or pass a loose stool that clears on its own. Steer a curious dog off the plant and it should bounce back fine.
Horses Toxic
A horse that grazes perilla can crash into severe respiratory distress, breathing fast, hard, and open-mouthed as fluid floods the lungs. It hits hard and often kills, so keep horses well clear of the plant, above all once it flowers and seeds in late summer.
Rabbits Caution
Since perilla ketone is a lung toxin in grazing mammals, a rabbit nibbling the foliage is a real risk, not a treat. Keep 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 while the plant flowers and seeds, and the outcome is often fatal. Pull it from pastures and hay before animals can reach it.
Birds Caution
Bird cases are not well documented, but the same lung toxin makes shiso a poor pick 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 are safe for people. The toxin that harms grazing animals stays a pasture problem, not a plate one.
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 forms, and picking one comes down to what you are after: 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 exactly why cooks grab it to color and flavor pickles like umeboshi.
Green shiso (aojiso)
The bright green flat leaves bring a milder citrus-anise note and go straight onto the plate fresh as a herb and garnish.
Bicolor / ruffled (chirimen) types
These crinkled, two-toned leaves run green on top and purple beneath, earning them a spot in the kitchen and the ornamental bed alike.
How to propagate
Shiso takes off from seed with barely any effort, and once it gets going it will happily sow next year's crop for you, sometimes more than you planned on.
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 jumps out of the gate from seed, 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 onto the surface and leave it uncovered, since it needs light to sprout, and a cold spell beforehand gives it a push. Give it 2 to 3 weeks to germinate and a few more to size up for picking, and once it settles in it will sow itself for years.
Myths
People eat shiso, so the whole plant has to be harmless to every animal.
The leaves really are safe for cooking, but Perilla frutescens carries perilla ketone, a documented cause of fatal lung poisoning in grazing cattle and horses. Safe on your plate is not safe in a pasture.
Shiso stays put wherever you plant it.
Not a chance, since it self-sows hard and has naturalized as an invasive weed across the southeastern and central United States, driving into pastures and woodlands. Cut the flower spikes before the seed sets to keep it in check.