The most delicious herbs (rau thom) hail from Vietnam – how to root them for free in just water


One of the things you notice quickly when sampling Vietnamese cuisine is the abundance of fresh herbs; herbs you probably have never seen or eaten.  Vietnamese herbs tend to be served on the side and used in dipping and raw in combination with the main dish.


On our trip through Vietnam, there were few meals that did not come with one of these big bowls of herbs.


After a few meals, we were able to quickly identify the different herbs.


While all these herbs are easily available in Asian markets in the USA, I was wondering if it would be possible to get these herbs to root from purchased herbs.  Yes,  I am happy to report, it is possible and not really that hard.


Here is a lineup of my rooting experiment.  I ended up using only water and sunlight and was pretty successful.  I have no doubt that if you used some actual rooting hormone, it would be even easier and quicker.  There is not much to discuss on the methodology.  Basically just place the herbs in water, place in a sunny window, change the water every few days and wait.  Some of these will root within days, some will take a few weeks.  If any of the herbs deteriorate (lose all leaves or rot), throw those out to keep the water clean.  Also, the age of the herbs is very important.  The fresher, the better.  Where I buy my herbs they actually mark the “packed on” day – try to get some that are packed the same day.

Here are the herbs that worked for me.


Vietnamese Balm/ Vietnamese Lemon Mint/ Kinh Giới  / Elsholtzia ciliata

These are delicious tasting like a combination of lemon, lemon grass, lemon balm and mint.  I find Vietnamese balm to be less strong than our western lemon balm.


Vietnamese Mint/Húng Cay/ Mentha x gracilis

This is very similar to our western peppermint, perhaps a bit milder in flavor.  These ended up getting infected with spider mites, so I cut them back, they recuperated nicely.  I also planted these last year in the yard and they have come back strong over the mild winter that we had here in zone 7b.

thai basil

Thai Basil / Asian Basil / Húng Quế / Ocimum sp

Most often associated with pho.  Nice sweet and spicy taste with hints of anise and licorice.  Delicious.


Rice Paddy Herb/ Ngổ Ôm / Limnophila aromatica

A plant I had never seen before – Citrusy with a hint of cumin – interesting combination. These are looking a bit sad, but I am hoping that they will start perking up now that spring has sprung.


Vietnamese Coriander / Hot Mint / Rau Răm /Polygonum odoratum

This is probably one of the fastest rooting plants that I have ever seen – indications of rooting were seen within 3 days.  The herb itself is spicy and hot with a hint of coriander.  These are supposed to be invasive – let’s see if they grow well.


Fish Mint/ Diếp Cá /Houttuynia cordata

A wild form of this is used as garden ornamental – it is highly invasive so be careful.  These have a sour and fishy taste – one of those herbs that you either love or hate.


Lemon Grass/ Xả / Cymbopogon citrata

These are commonly found in regular supermarkets nowadays.  Easily rooted in water and then transferred to soil they will grow fast during the warm season.  Unlike the other herbs, lemon grass is too fibrous to eat raw, but is great in cooking and to make tea.  As the name says, it has a strong taste of lemon.

Any you have tried to root?

1 thought on “The most delicious herbs (rau thom) hail from Vietnam – how to root them for free in just water”

  1. I just started rooting and so glad to have found your post. I haven’t the slightest idea about planting but decided to start. Not knowing where to start, I called up mom. She said to root and plant. I started rooting perilla and spearmint. As a matter of fact, I just planted them in pots today. I’d love to hear your progress so I know what to expect and do next with them.


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