Vietnamese Coriander (Vietnamese mint) care

Light

Bright but filtered. Vietnamese Coriander burns within days in unfiltered south-facing summer sun, and stops growing within months in deep shade. Full sun to partial shade. Outdoors a sheltered spot with morning sun and afternoon shade is ideal in hot climates, as leaves can scorch in intense midday heat. Indoors, grow on a bright sunny windowsill; it tolerates a few hours of filtered direct sun. If you only have a south window, set the plant back 1.5 m or hang a sheer curtain — both knock the intensity down into the right range.

Watering

Watering vietnamese coriander: keep soil consistently moist to wet; water container plants daily in warm weather. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. This is a marsh-margin plant with high water needs that never wants to dry out. Keep the soil consistently moist to wet but avoid stagnant waterlogging. It wilts quickly when underwatered but recovers fast once rehydrated. Containers dry out faster and may need daily watering in heat.

Soil and pot

Vietnamese Coriander grows best in rich, moisture-retentive but well-draining potting mix or garden soil. Prefers fertile soil high in organic matter that holds moisture. Tolerates sandy, loamy or clay soils across mildly acidic to mildly alkaline pH. Enrich garden beds with compost; for pots use a quality mix amended with extra organic matter to retain moisture while still draining. 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

Vietnamese Coriander sits happiest at around Moderate to high (50%+) humidity and 14-30°C (optimal); damaged below ~5°C and killed by frost (57-86°F (optimal); damaged below ~40°F and killed by frost). A tropical, humidity-loving herb that thrives in warm, humid conditions. It tolerates average household humidity but grows lushest with higher moisture in the air; very dry indoor air can dry the leaf margins, so group with other plants or mist in heated rooms. If you keep the room above 14 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 vietnamese coriander sparingly. Feed with a balanced or nitrogen-leaning fertiliser about twice a month during the warm growing season and roughly once a month in cooler periods. Container plants need more frequent feeding because nutrients leach out with regular watering. Avoid over-fertilising, which can dilute the leaves' aromatic, peppery flavour. 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 vietnamese coriander in the Growli community. Each is annotated with the most common cause so you know where to start.

• Wilting / leaf collapse — The most common complaint, almost always from the soil drying out. This water-loving herb flops fast when thirsty but usually perks back up within hours of a thorough watering. Keep it consistently moist.
• Aphids — Soft-bodied sap-suckers that cluster on tender new growth. Dislodge them with a firm spray of water; for heavier infestations use insecticidal soap, rinsing edible leaves well before use.
• Spider mites — Tiny mites that thrive in hot, dry air, causing fine stippling and faint webbing on leaves. Raise humidity and hose down the foliage; persistent cases respond to insecticidal soap or neem.
• Leaf scorch in intense sun — In very hot climates, harsh midday sun combined with any moisture stress can dry and brown the leaf edges. Provide afternoon shade and keep the root zone reliably moist.
• Frost / cold damage — Frost-tender and killed by freezing temperatures; growth slows and leaves blacken below about 5°C (40°F). Bring containers indoors or take cuttings before the first frost to overwinter.
• Leggy, sparse growth — Stems sprawl and bare at the base in low light or when left unharvested. Site in bright light and pinch or harvest tips regularly to encourage dense, bushy regrowth.

Propagation

Extremely easy from stem cuttings — it roots freely at the nodes. Take 10-15 cm (4-6 in) stems, strip the lower leaves, and stand them in water (changing it every few days) or push directly into moist soil; roots form within one to two weeks. A bunch bought fresh from an Asian grocery can be rooted this way. Established clumps can also be divided in spring or autumn. 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

Vietnamese Coriander is mildly toxic to pets. Persicaria odorata is not individually listed in the ASPCA toxic or non-toxic plant database, and its genus (Persicaria/Polygonum) has no ASPCA-listed members. However, related plants in the same buckwheat family (Polygonaceae) that the ASPCA does list — rhubarb, dock/sorrel and buckwheat — are all toxic to cats and dogs due to soluble calcium oxalates. With no clean genus precedent, treat it as potentially mildly toxic and verify with your vet before allowing pet access. 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.

Vietnamese Coriander deep-dive guides

Every aspect of vietnamese coriander care, each with its own calibrated guide:

• Vietnamese Coriander watering schedule
• Vietnamese Coriander light requirements
• Best soil mix for vietnamese coriander
• Vietnamese Coriander fertilizing guide
• When to repot vietnamese coriander
• How to propagate vietnamese coriander
• Vietnamese Coriander growth rate & size
• Vietnamese Coriander cold hardiness
• Vietnamese Coriander temperature & humidity
• Is vietnamese coriander toxic to cats & dogs?

Related guides

Vietnamese Coriander is also known as Vietnamese coriander, Vietnamese mint, rau ram, Cambodian mint, laksa leaf, and Asian mint.

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• All 609 plant care guides in the Growli library