Red Shiso (Purple Perilla) care

Light

In the wild red shiso grows on the bright edge of a forest canopy, not in the canopy and not in the open. Indoors, that translates to within a metre of an unobstructed window, sheer curtain optional. Grows in full sun to part shade; sun deepens the red-purple leaf colour, while a little afternoon shade in hot climates prevents wilting and scorch. Too much shade gives leggy plants with muddier colour. The fastest test: a hand held at the leaf casts a soft-edged shadow at noon — sharp shadow means too much sun, no shadow means too little light.

Watering

Aim for keep evenly moist; water every 2-4 days, more in heat for red shiso, but treat that as a starting point rather than a rule. A south-facing summer windowsill will dry the pot twice as fast as a north-facing winter room. Lift the pot; if it feels noticeably lighter than it did wet, water it. Likes consistently moist soil and wilts dramatically when dry, though it usually recovers after watering. Avoid both drought stress and waterlogging; mulch helps hold moisture in summer.

Soil and pot

Red Shiso grows best in fertile, moist, well-drained loam. Prefers rich, organic, moisture-retentive soil with good drainage at a near-neutral pH around 5.5-7.0. It tolerates average ground but grows lushest and most colourful in fertile soil. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Red Shiso sits happiest at around 40-60% humidity and 18-28°C (64-82°F). Comfortable in average to moderately high humidity typical of warm summers. It is not fussy, but good airflow around the dense foliage helps prevent fungal leaf problems. If you keep the room above 18 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed red shiso sparingly. A moderate feeder grown for abundant leaf. Work compost into the soil and apply a balanced or nitrogen-leaning liquid feed every few weeks for lush growth. Avoid excessive nitrogen, which produces soft leaves at the expense of flavour and colour intensity. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on red shiso in the Growli community. Each is annotated with the most common cause so you know where to start.

• Wilting in heat or drought — Leaves collapse dramatically when the soil dries or sun is intense. Keep soil evenly moist, mulch, and provide afternoon shade in hot spells; it usually rebounds after watering.
• Prolific self-seeding — Left to flower, it seeds everywhere and can become weedy. Pinch out flower spikes to prolong leaf harvest and prevent unwanted seedlings.
• Legginess — Unpinched plants in low light grow tall and bare. Pinch tips regularly from young to force bushy, well-branched, leafier growth.
• Frost death — Any frost kills it outright as a tender annual. Harvest before the first cold snap or grow in pots moved indoors to extend the season.

Propagation

Grown from seed, which needs light and warmth to germinate, so surface-sow and barely cover. It self-seeds freely, producing volunteer plants each year; softwood cuttings also root quickly in water or moist soil for extra plants. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Red Shiso is toxic to pets. ASPCA-listed as toxic to dogs, cats, and horses (entry: Perilla mint, Perilla frutescens). Toxic principles are essential oils, including perilla ketone. Large ingestions cause vomiting and diarrhoea in dogs and cats; the perilla ketones cause severe respiratory disease (atypical interstitial pneumonia) in horses and ruminants, so keep pets and livestock away. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Red Shiso deep-dive guides

Every aspect of red shiso care, each with its own calibrated guide:

• Red Shiso watering schedule
• Red Shiso light requirements
• Best soil mix for red shiso
• Red Shiso fertilizing guide
• When to repot red shiso
• How to propagate red shiso
• Red Shiso growth rate & size
• Red Shiso cold hardiness
• Red Shiso temperature & humidity
• Is red shiso toxic to cats & dogs?
• Is red shiso toxic to cats?
• Is red shiso toxic to dogs?

Related guides

Red Shiso is also commonly called Purple Perilla or Aka Shiso.

• Basil care — light, water and common problems
• Herb garden care — light, water and common problems
• Mint care — light, water and common problems
• All 1284 plant care guides in the Growli library