If you’ve ever babied a pot of cilantro through late spring only to watch it shoot up, flower, and quit the moment the weather turned warm, you already understand the appeal of Vietnamese coriander.
This is the herb that does the opposite. It shrugs off heat and humidity, grows faster than you can eat it, and keeps handing you that bright, citrusy-peppery bite all season — no bolting, no drama.
Better yet, it’s one of the easiest plants you’ll ever propagate. A single stem from an Asian grocery can turn into a lifetime supply.
By the end of this guide you’ll know how to start a plant for free, keep it happy through summer and winter, sidestep the mistakes that make it sulk, and turn those spicy leaves into dinner.
The Quick Version
- It’s not true cilantro or mint — just a look-and-taste-alike that happens to love heat.
- Grow it in a pot to keep it from wandering, in rich soil that stays damp.
- Give it warmth, steady moisture, and afternoon shade where summers are fierce.
- Feed it — a starved or root-bound plant simply stops growing.
- Harvest the young leaves often, and bring it indoors before frost.
| Botanical name | Persicaria odorata (once Polygonum odoratum) |
| Family | Polygonaceae, the knotweeds — not related to cilantro or mint |
| Also called | Rau răm, Vietnamese mint, Cambodian mint, hot mint, laksa leaf |
| Type | Tender perennial; grown as an annual or houseplant where it’s cold |
| Hardiness | Roughly USDA zones 9–11; protect it below about 45°F (7°C) |
| Light | Full sun to part shade (afternoon shade where summers are hot) |
| Water | High — keep the soil constantly moist; it genuinely likes wet feet |
| Mature size | About 12–24 in (30–60 cm) tall, spreading outward |
| First harvest | Roughly 4–8 weeks after rooting a cutting; pick young leaves |
What Vietnamese Coriander Actually Is
Here’s the first surprise: despite the name, this plant isn’t a kind of cilantro, and despite one of its nicknames, it isn’t a mint either. Botanically it’s Persicaria odorata, a member of the knotweed family.
The reason it tastes so much like cilantro is a quirk of nature called convergent evolution — two unrelated plants stumbling onto a similar flavor.
That family difference is exactly why it behaves so differently in the garden, thriving in the heat that sends real cilantro straight to seed.
It travels under a lot of names. In Vietnam it’s rau răm; across Southeast Asia you’ll hear Vietnamese mint, Cambodian mint, hot mint, and laksa leaf, after the spicy noodle soup it flavors in Malaysia and Singapore.
Knowing those aliases is genuinely useful when you’re hunting for a plant to buy.
The flavor is bold and layered: a fresh, lemony top note followed by a warm, peppery heat that builds — hence “hot mint.” The young leaves carry the best of it, which is why you pick this herb little and often.
One happy bonus: some people find regular cilantro tastes like soap.
That’s a real genetic quirk — a variation in a smell receptor gene (OR6A2) that makes certain people extra-sensitive to the compounds in cilantro, and it affects an estimated 4–14% of people.
Because Vietnamese coriander is a completely different plant, most cilantro-haters can eat it happily, though a rare few still catch a faint soapy note.
How to Get Your First Plant — For Free
You almost never start this herb from seed. It rarely flowers outside the tropics, and when it does, the seed usually isn’t worth planting.
The good news is that it roots so eagerly from cuttings that seeds would just be extra work.
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Root a bunch from the grocery store
This is the cheapest houseplant trick going. Grab a fresh bunch of rau răm from an Asian market and turn a handful of stems into plants:
- Choose the freshest bunch you can find — firm stems, no wilting or yellowing.
- Pick a few sturdy stems and strip the leaves off the bottom couple of inches, leaving a leafy tuft on top.
- Stand them in a glass of clean water so the bare nodes — the little joints where leaves meet the stem — sit underwater. Roots grow from those nodes, not from the smooth stem between them (this is where it differs from basil).
- Set the glass somewhere bright but out of harsh sun, and change the water every couple of days so it stays fresh.
- In about a week you’ll see white roots. Once they reach 2–3 in (5–8 cm), pot the cutting up in damp soil.
Watch out for one trap: a cutting sitting in plain water will root and then stall — it can’t truly get growing until it’s potted into soil, so move it once the roots are a few inches long rather than waiting for new leaves in the glass.
Fresh growth after potting tells you it has taken.
Or buy a small plant
If you’d rather skip the wait, look for starter plants at herb-focused nurseries, well-stocked garden centers, or online specialty growers.
It isn’t always labeled clearly, so search every alias — rau răm, Vietnamese mint, laksa leaf — and check the fresh-herb shelf at Asian grocers, where a rooting bunch costs a fraction of a nursery pot.
Planting It So It Thrives (Without Taking Over)
- Reach for a pot.
Like mint, this herb creeps along the ground and roots wherever a stem touches down, so in the right spot it can spread with real enthusiasm — some gardeners call it invasive.
A container is the simple fix. Choose one at least 8–12 in (20–30 cm) across with good drainage holes.
If you do want a patch in the ground, give it a damp, low corner where it can roam without smothering slower neighbors like rosemary.
- Give it rich, moisture-holding soil.
Mix plenty of compost into potting soil or garden bed. It isn’t fussy about pH — acidic, neutral, or alkaline all suit it — so you can skip the test kit and focus on feeding and moisture instead.
- Wait for warmth.
This is a heat-lover with zero frost tolerance, so plant it out only once all danger of frost has passed and the soil has warmed, usually spring to early summer.
- Try the buried-stem trick.
Set a few stems into a pot filled only halfway with soil.
Once they’re growing well, strip the lower leaves and top the pot up with more soil so the buried stem roots along its nodes — the same logic as planting a tomato deep.
You’ll get a fuller, sturdier, more productive plant.
What It Really Needs: Water and Warmth
Get these two things right and everything else is a rounding error.
Water — it likes wet feet
This herb grows wild along pond edges and paddy fields, and it never forgot. Keep the soil constantly moist; if it dries out, the leaves wilt fast.
The reassuring part is how forgiving it is — give a wilted plant a good soak and it usually perks right back up.
A container in summer heat may need checking every day, and a layer of mulch helps hold moisture between waterings.
- About that “overwatering” warning:
You’ll see plenty of advice about root rot, and it’s worth understanding rather than fearing.
Rot doesn’t come from too much water — it comes from stagnant, airless, soggy soil in a pot that drains poorly.
In free-draining soil, or grown deliberately as a bog plant, this herb is nearly impossible to overwater.
- The lazy-gardener method:
Stand a pot of soil inside a bucket and keep an inch or two of water in the bottom, topping it up whenever you water everything else. It thrives this way as an “emergent” plant, roots wet and leaves in the air.
If mosquitoes start using the water, simply let the surface dry out once a week — that breaks their cycle — or add a couple of small fish. It’s the most hands-off way to grow it.
Warmth and light
Vietnamese coriander is happiest between about 70–90°F (21–32°C). Growth crawls below roughly 50°F (10°C), and it isn’t frost-hardy — but the common line that it “dies at the first frost” oversells the danger.
A light frost often just knocks it back, and if the roots don’t freeze it frequently returns in spring. An established plant, or a sheltered spot against a warm wall, can carry it through a mild winter in a borderline climate.
Sun or shade? Both answers are right. You’ll see it listed as a full-sun plant and as a shade-lover, and the truth depends on your climate. In mild or cool regions, give it all the sun you can.
Where summers are blazing, morning sun with afternoon shade is the sweet spot — too much fierce, direct sun makes the leaves tough and bitter and leaves the plant wilting by noon.
Indoors it’s the reverse problem: give it as much bright light as possible, ideally a south-facing window, plus a grow light through the dim weeks of winter.
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Feeding, Trimming, and Why Your Plant Suddenly Stalls
The stall nobody warns you about
Here’s the single most common frustration with this herb: it roots beautifully, then just… sits there for weeks, doing nothing.
The cause is almost always hunger or cramped roots. It’s a fast, greedy grower, and the moment it exhausts the nutrients or fills its pot, it stops cold. Cutting it back won’t restart it — feeding will.
A dose of balanced liquid feed or a scoop of compost usually wakes it up within days, and if the roots have filled the pot, move it up a size or divide it.
Feed on a rhythm, but don’t overdo it
A balanced liquid feed every couple of weeks in warm weather, dropping to monthly when it’s cool, keeps it productive.
Potted plants need feeding more often because nutrients wash out with all that watering.
Resist the urge to overfeed, though — too much fertilizer gives you a flush of soft, watery leaves with far less of that signature flavor. A little restraint tastes better.
Trim early and often
Pinch the growing tips regularly. It keeps the plant bushy, stops it going leggy and woody, and the trimmings head straight for the kitchen.
Don’t be timid, either — you can cut it back hard, almost to the soil line, the way you’d treat sage or thyme, and it bounces back fuller than before.
Dealing With Pests and Unhappy Leaves
Outdoors, in a spot it likes, this is a remarkably trouble-free plant. The one real exception is aphids, which adore the tender growing tips — especially on plants brought inside for winter.
Knock them off with a firm spray of water and repeat every few days, or reach for a little neem oil or insecticidal soap. Indoors, also keep an eye out for spider mites and whiteflies, which move in when the air is dry.
The leaves will usually tell you what’s wrong:
- Yellowing lower leaves are often just old age — or a sign of soggy, airless soil, so check your drainage.
- Brown, crispy, or shriveled edges usually mean it dried out, got scorched, or took a beating from dry wind. Trim them off and keep the water coming.
- A few damaged leaves on a plant that’s still pushing out new growth are nothing to lose sleep over.
Getting It Through Winter
Because it can’t take frost, in cold regions this is a container plant that comes indoors for the cold months.
Before the first frost, move pots to your brightest window and add a grow light through the darkest weeks to keep new leaves coming.
Ease off harvesting while growth is slow — the plant is coasting, not producing.
The best insurance is almost too simple: keep one cutting rooting in a glass of water on the windowsill all winter.
If your main plant sulks or gives up, you’ve always got a backup ready to pot on when the weather warms.
For plants in the ground in borderline zones, mound a deep mulch over the roots in late autumn and hope for a spring return.
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Harvesting and Keeping Your Leaves
When and how to pick
Start harvesting once the plant is settled in and actively growing, often 4–8 weeks after a cutting takes.
Always go for the young leaves — they’re tender and full of that lemon-pepper punch, while older leaves turn tough and bitter.
Snip stems and pinch the growing tips as you harvest; cutting just above a leaf node and leaving a few inches at the base keeps the plant pumping out more.
Store it fresh
It’s at its best within a week.
Stand the cut stems in a jar of water, drape a loose plastic bag over the leaves, and keep it in the fridge — treat it like a little bouquet.
Alternatively, roll the leaves in a barely-damp paper towel inside an unsealed bag.
Preserving for later
Fresh really is best here, and drying disappoints — most of the aroma simply vanishes.
Freezing holds on to far more flavor: chop the leaves and freeze them in bags, or pack them into ice-cube trays topped with a splash of water or oil.
Frozen leaves thaw soft, so save them for soups and curries rather than fresh garnish.
Cooking With Rau Răm (and a Quick Safety Note)
Go easy — it’s bold
This is a strong, assertive herb: lemon and pepper with a warm, slightly musky bite. Use about half of what you would of cilantro, and pair it with dishes that can stand up to it.
Heat drives off its fragrance, so stir or scatter the leaves in at the very last minute rather than cooking them long.
Here’s the simplest way to fall for it: tear a few young leaves into the bottom of a bowl, then ladle steaming chicken broth straight over the top.
The heat wilts them just enough to release that citrus-and-pepper aroma, and the first spoonful tastes like something you’d order at a restaurant.
It shines in fresh spring rolls, phở, and laksa — that’s where the “laksa leaf” name comes from.
It’s essential in Vietnamese chicken salad (gỏi gà), classic with duck-egg dishes like trứng vịt lộn, and brilliant alongside seafood and rich meats, where it cuts through fishiness and fat.
Beyond Southeast Asian cooking, it perks up herb dips, noodle bowls, and salads. It plays especially well with lime, lemongrass, ginger, chili, garlic, coconut, and tomato.
A quick word on safety
Rau răm has a long history in folk medicine — for digestion, colds, and skin complaints — but those uses aren’t backed by solid clinical evidence, so enjoy it as food rather than as a remedy.
More important: if you’re pregnant, it’s wise to limit yourself to the occasional garnish, or skip it altogether.
It has traditionally been used to bring on miscarriage, and reliable safety data is thin, so when in doubt, leave it out and check with your doctor.
(You may also hear that it lowers libido; there’s no real scientific support for that, and it would take large, regular amounts to matter — a few leaves on dinner won’t.)
Frequently Asked Questions
Can I grow Vietnamese coriander from seed?
Almost never. It rarely flowers outside the tropics, and when it does, the seed usually isn’t viable.
That’s actually a gift — cuttings root so readily that one grocery-store stem or a small nursery plant is all you need to get started.
What’s the difference between Vietnamese coriander and culantro?
They’re two different plants that both echo cilantro. Culantro (Eryngium foetidum) has long, flat, saw-toothed leaves and reseeds itself freely.
Vietnamese coriander is the creeping herb with narrow, pointed leaves and reddish stems. Both show up in phở, and neither is botanically related to true cilantro.
Why are my plant’s leaves turning red or purple?
Usually it’s nothing to worry about. Stronger sunlight deepens the natural burgundy markings and can redden the stems, and a cold snap can do the same.
As long as the plant is firm and still growing, those red and purple tints are just its response to light and temperature.
How many plants do I actually need?
For most households, a single plant is plenty. It grows fast and rebounds quickly after harvesting, so one healthy plant usually keeps a family in leaves all season.
Start a second only if you cook with it constantly — or to keep one as a winter backup.
There’s no rau răm at my store — what can I use instead?
For fresh, raw uses, cilantro with a little mint stirred in gets you in the neighborhood, and culantro is a decent stand-in for cooked dishes.
Just know that nothing is a perfect match in laksa or a traditional chicken salad, where its particular heat is part of the dish. Once you find it, root a stem and you’ll never have to substitute again.
From Pot to Plate
Vietnamese coriander pays back almost no effort with a lot of flavor.
Nail the essentials and the rest looks after itself: keep it warm, keep it wet, give it a pot so it can’t wander, feed it before it stalls, and always pick the youngest leaves.
Bring it in ahead of frost and it’ll carry on through the cold on a bright windowsill.
The real magic is that this is a plant-once, harvest-for-years kind of herb.
Once it settles in, you’ll have a steady supply of that bright, peppery bite — and you can finally stop paying for sad, wilted bunches that dissolve in the crisper drawer.
So here’s your nudge: next time you pass an Asian grocery, pick up the freshest bunch of rau răm you can find and stand a few stems in water tonight.
In a week you’ll have roots. By late summer, you’ll have dinner.
source https://harvestsavvy.com/growing-vietnamese-coriander/
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