Vietnamese Fish Mint

I have been growing Vietnamese Fish Mint  (Houttuynia cordata) for years, yet for some reason I have never written a blog post on it before now.  

This plant has many common names, including dokudami, 'poison blocking plant',  lizard tail, heartleaf, fishwort, bishop's weed, and it has a heap of other common names too.  I usually just call it 'fish mint'.

Vietnamese Fishmint is a perennial vegetable that not at all related to mint.  It is edible and used as a vegetable or herb, it has a long history of medicinal use, as well as a long history as a remedy for poisoning.  

This is an essential vegetable in Vietnamese cooking, and appears to be eaten extensively in South East Asia.  This is very uncommon in Australia, yet extremely simple to grow and very productive.

Vietnamese fish mint in flower

Fish mint has a strong and rather distinctive smell.  Some people love the taste of fish mint, others not so much.  Some people liken its smell to oranges, others think it smells like fish, to others it smells like the gravel in the bottom of a fish tank.  

Vietnamese Fish Mint tends to be eaten raw, or only lightly cooked/wilted.  It does taste a lot like fish sauce, and can be used to make a vegetarian fish sauce.  When raw it tastes a bit too...I'm not sure how to explain it...perhaps too 'metallic' for my liking.  Once slightly cooked I prefer the taste.  Other people tell me they can't taste any of the metallic taste that I notice, so I guess it differs from person to person.  

Fish mint can be used to make a Vegan Fish Sauce.  Seriously!  How cool is that.  I found a recipe that I shared below, but if you have a better recipe and are willing to share it I would love to learn more.  

It is also used to make a medicinal "dokudami" herbal tea.  I have made this a few times, it tastes nice but I find the smell to be a little too strong for me.  My kids have tried the herbal tea, they like it.  I have made herbal tea using fish mint as well as other herbs such as lemon balm.  This was nicer, but I still found the fish mint to be overpowering.  

The rhizomes are used in a bunch of different herbal remedies, many of which have been proven to be effective.  Unfortunately I don't know how to make these medicines.  Presumably just eating the rhizome is enough to gain some benefit.  I find the rhizomes to be less overpowering than the leaves.  

Vietnamese Fish Mint 

Many animals, including chickens, quail, ducks, guinea pigs, sheep, and pigs gladly eat fish mint.  It has a lot of nutrients and some medicinal benefit.  Interestingly, fish mint has been demonstrated in many peer reviewed papers to protect chickens from bronchitis (https://pubmed.ncbi.nlm.nih.gov/21848486/), as well as treat coccidiosis in chickens and lambs as effectively as commercial coccidiosis medication.  I am tempted to grow this in a hanging pot in the chicken run so the hens can get the benefits of an organic coccidiosis treatment.  

There are several varieties of this plant.  I grow the most vigorous green version with single flowers.  There is a green one with double flowers, and there is also a multicoloured variegated one that looks really pretty and spreads less vigorously.  I am told the green one is not only more vigorous, but also more potent.  My chickens gladly eat the leaves, but I don't give them many, so I am glad I grow the most potent version.  

The leaves of the variety I grow are green, heart shaped, and they look very similar to buckwheat leaves.  The flowers are white and not overly interesting.  Bees and other insects visit the flowers, but never seem overly keen on them.  I am happy to say that the variety I grow never produces viable seed. 

Fish mint on left, buckwheat on right 

Fish mint grows extremely vigorously.  Let me stress, it is extremely vigorous.  One or two pots of this plant will be more than enough for the average household.  I am happy to say mine does not set any viable seed, ever, which makes it much easier to control.  Never grow this in the soil or it will take over your yard, and your neighbour's yards, and every time you walk in the yard or mow it will smell like fish.  Grow it in a pot, but never in the garden bed.  

I grow most of my fish mint in a container, and the container is on pavers.  My main one is in a plastic tub that we drilled holes in, it's not very deep but it is wide to allow the plant to spread, but any plant pot would do.  The rhizomes will try to escape through the drainage holes, but they can't cross the pavers.  

I have been growing this plant for seven or eight years and it has never escaped on me.  I also grow some in pots on wire shelves in my greenhouse, but these are being grown out to sell at markets and through the post.  

Fish mint escaping it's pot

Fish mint does not produce seed, or at least the one I grow has not produced any seed in the time I have grown it.  This is not a problem because it is easily divided to produce more plants.  If it did produce seed I am not sure that I would be willing to grow it because it spreads so vigorously.  

This plant is not related to mint (Mentha sp) and does not taste or smell even vaguely similar to mint.  I believe the word 'mint' in its common name is probably due to the way it spreads aggressively via underground rhizomes like mint.  

As well as being easy to divide, this plant grows readily from cuttings.  Planting cuttings in soil seems to result in 100% strike rate if the soil is kept damp.  I have only tried striking a cutting in water once, this grew well for me but not as fast as the ones planted in soil.  

I have never tried to restore fertility and grow from seed.  I prefer that it does not produce seed as it stops it from escaping into my yard.  I have considered getting the prettier variegated form, but don't know if a second clone would increase the possibility of viable seed, so for that reason have resisted the urge to get the variegated form.

When grown in a pot, some rhizomes will try to escape through the drainage holes.  Any rhizomes that try to escape the drainage holes can be roughly torn off, planted in a pot of damp soil, and will produce more plants.  They grow very quickly from rhizomes and produce large healthy plants very fast.  

Fishmint rhizomes potted up and ready to grow

Fish mint grows well in part shade, and survives in full sun.  It seems to prefer damp areas, but does not need to be waterlogged to grow well.  I have heard it can be grown as an emergent water plant, but haven't grown it like that myself.

Mine gets pretty dry at times over summer, if it looks like it is burning off I give it some water and it bounces back quickly.  I imagine if the soil got too dry for an extended period it would die.  This plant has a strong will to live, and tends to recover easily from all kinds of poor treatment.  

I have seen fish mint growing in floating pots on a pond.  I love the looks of this, and think it would do well in cleaning the pond water when grown like this.  Care would need to be taken that the pot did not get too near the edge and allow the plant to set root into the mud on the bank, as it would be difficult to remove once it became established.  

Fishmint goes mostly dormant over the winters here.  I say 'mostly dormant', because some years all the above ground parts die back, and other years it just looks scraggly and keeps a few leaves here and there.  The underground rhizomes survive very cold temperatures, easily coping with -10C with frozen solid soil, and it grows vigorously once the warmer weather returns.  

I am told that people (often in the US) grow the weaker variegated version of fish mint under trees or near ponds where it looks lovely.  They soon regret this as it takes over the yard, and it smells like fish every time they mow.  This is where my hesitation to grow it in a floating pot on a pond comes from.

Spraying does not kill this plant, herbicides easily kill the above ground parts, and it quickly resprouts from many underground rhizomes.  This is a plant that does not want to die.  I have heard that it can survive under weed mat for years, and pop up once their is a rip in the weed fabric.  

The simple way to deal with this is don't grow it in the garden bed.  Grow it in a pot, and have the pot on pavers.  As I mentioned, mine has never escaped and I have grown it for seven or eight years.  

Vegan Fish Sauce Recipe 

I found a recipe for vegan fish sauce here, it is so simple.

Ingredients: 1 cup packed fish mint leaves; 3 Thai chili peppers; 2 cloves garlic; 1/3 cup sesame oil; 2 tbsp rice wine vinegar 

Instructions: Puree all ingredients in a food processor. Transfer to a bowl and serve.

Other Fish Mint Recipes 

I also found a recipe for Fish mint that uses rhizomes as well as leaves.  It also is very simple.

Ingredients: 1/4 cup shredded young fish mint leaves, 1/4 cup chopped fishmint rhizomes, 4 tablespoons soy sauce, 2 tablespoons rice vinegar, 1 tablespoon fried chili crisp or chilli oil, 1 tablespoon chopped coriander cilantro, 1 tablespoon chopped scallions.

Instructions: Combine all the ingredients and toss shredded fishmint leaves and rhizomes. Chill for 10 minutes before serving.

As well as another recipe that includes tofu.

Ingredients: 200 g fish mint stems, broken into 4 cm lengths (or lotus stems), 8 fried tofu cubes, 1 handful of chopped mint leaves, 1/2 cup coriander, roughly sliced, 1/2 cup garlic chives, roughly sliced, 1/2 cup red peppers, finely sliced 

Dressing: 3 tbsp light soy, 2 tbsp black vinegar, 1 tbsp brown sugar, 2 spring onions, sliced, 1/2 tsp dried chilli flakes, 3 garlic cloves, diced, 4 cm piece of ginger, finely sliced.

Instructions: To make the dressing, in a bowl, combine the light soy sauce, black vinegar, brown sugar, spring onion, chilli flakes, garlic and ginger. Stir well and set aside for a few minutes to infuse.

In a large mixing bowl, combine the fish mint stems, tofu, mint, coriander, garlic chives and red peppers. Add the dressing and toss to combine. Transfer to a serving platter.

I have only shared a few recipes above.  There seem to be a host of similar recipes around, plus many families have their own family recipes.  If you have a good recipe and are willing to share it let me know and I can add it.  

Vietnamese fish mint

I mentioned earlier that this plant is vigorous, and I find the smell to be overpowering.  Some people adore fish mint, so much so that they will drive an hour each way to pick up a plant from me.  

I don't want to detract from the many benefits of this plant, so please read my opinion of its smell while keeping in mind that different people like different things, and that some people adore fish mint.  Fish mint is also incredibly healthy to eat, both people and animals benefit from eating it, so please don't take my comments to mean that you should not grow and eat this.  

I really can't cope with the smell of fish mint.  It is too strong for me.  Even repotting this can be too much for me at times.  

Other people comment how they adore fish mint, and most people I sell it to rave about it.  I had a few people drive out to buy fish mint plants from me cry tears of joy.  They told me they cried because it is a taste of home, a very dear memory, and they were fearing that they would never be able to eat this again after moving to Australia.  

While I don't think anyone should ever grow this in the garden do to how rampantly it spreads, I think this is well worth growing to see if you like it.  If you like the taste it is increadbly healthy to eat.  I also know that this plant makes a cherished gift to Vietnamese or Chinese friends.  

This plant is very useful for making Vietnamese spring rolls, Pho, and dokudami herbal tea.  People who buy this from me often say that they are thankful that they will never be without it again.

I have been selling organically grown Fish Mint plants for years through my for sale page along with other perennial vegetables I have for sale in Australia.  If you are interested go and have a look.  I either sell small fish mint plants, well rooted cuttings, or dormant rhizomes, depending on the time of year.  If selling rhizomes I tend to include extras, they will all grow once it starts to warm a little.  Over winter they are mostly dormant, and look very shabby, but they grow like mad once the weather warms.