Vietnamese coriander (
Persicaria odorata)
is an excellent perennial herb which should be more widely grown at
home but is not easy enough to find. It has
a bunch of different common names including Vietnamese mint, laksa herb, hot mint, Cambodian mint, praew leaf, and
many more.
Vietnamese Coriander is not related to coriander at all, it is not related to
the mint family, but it is eaten in Vietnam and is often used in laksa.
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Vietnamese Coriander - growing as an emergent plant |
I
first saw this herb at a training day (I swapped it for some perennial
leeks), the lady tore off a small cutting for me, then said something
about it not surviving
until I got home as it was the middle of summer and the course still
had a few hours to go. I put the little cutting in my pocket and when I
got home it was bruised, limp and looked dead, so I put it in a cup of
water in the shade. It looked very dead to
begin with but it grew roots within a few days and I have had it ever
since.
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Vietnamese Coriander rooted cutting |
How to grow Vietnamese Coriander
I
thought Vietnamese coriander was always grown as an emergent plant with
its roots and stems under water and its leaves always sticking out of
the water. I have
grown it this way for a few years and it has done rather well for me. Recently I
have seen it for sale with other terrestrial herbs, not sitting in a
tray of water, but having a tag that says to water it well and not allow
it to dry out at all. I guess it is more
versatile and hardy than I realised.
Honestly,
I think growing it as an emergent is far more simple than trying to
keep it well watered. I grow this herb in the same way that I grow
Chinese water chestnuts
or duck potatoes or water cress, sometimes I even grow them together in
the same bucket. A bucket or something similar with soil a few inches
from the top, filled with water is easy to set up and maintain, as is
submerging a pot of soil in a bucket of water.
Each day when watering the rest of the vegetables you simply top up the
water in the bucket. If the water does dry off, the soil remains damp
enough for your plant.
If there are mosquito issues either put in some
small fish (research which ones to use first
and always stay clear of Gambusia) or simply let it dry out once a
week. The soil needs to remain moist for this plant to flourish, but if
there is no free water on top of the soil the mosquito larvae die or
are eaten by ants pretty fast. Doing this weekly
will ensure that the mosquito do not have time to hatch, pupate and metamorphose into adults. Not watering once a week is simple enough to
do, or to not do as the case may be.
When
growing in a bucket of soil and water the waterlogged soil tends to
prevent any serious weed growth as few weeds can handle long periods of
submerged roots.
The presence of open water tends to encourage frogs, superb fairy wrens
and other tiny insectivorous animals which are beneficial for the garden.
Other
than never letting this plant get dry, don’t let it run out of space or
nutrients. It will grow very fast, but if it runs out of space to grow
or uses all
the available nutrients it will stop growing completely. The plant
will not die, but if it is not growing then it is not supplying you with
leaves so there is no point having it. I have taken cuttings of this
and put it in a glass of water, the cutting grows
roots very fast, but then growth stops and it does nothing, absolutely
nothing, for months. This is because it needs nutrients, plant it in
the soil and let it do its thing. A similar thing happens when grown in
a small pot of soil, it rapidly grows to fill
the space it has been given, then it stops growing completely. Cutting
it back hard does not encourage a new flush of growth, only feeding it
seems to make a difference. This is as simple as tipping a little
poultry manure into the bucket.
Vietnamese
coriander does not like frost and very cold weather will significantly
slow its growth. As long as you keep a little of this plant out of the
frost it
will survive to regrow for you when the weather warms. It is even
possible to keep a cutting alive in a glass of water over winter if
needed. Try to keep in mind that in a glass of water this cutting will
quickly look bad, stop growing, and the leaves may
turn red and the leaves may go bitter, or the leaves may even drop off if it is too cold. I know
someone in Orange NSW who put bubble wrap over her plant to keep it
alive over winter. Any part that gets hit by frost will die off, but if
any of the plant is alive it will regrow fast enough in warmer weather.
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Vietnamese Coriander cutting starting to grow in water |
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Vietnamese Coriander growing in soil and water in a milk bottle |
How to propagate Vietnamese coriander
I
am told that Vietnamese coriander will not flower outside of the
tropics due to daylight sensitivity issues as well as strict
temperature/humidity requirements.
This is not the case at all. I have had Vietnamese coriander flower
for me and I have never lived in or anywhere near the tropics. The flowers are
small, uninteresting and white.
I don’t know if it needs a second clone
for pollination due to self-incompatibility
issues, or if the seeds need special conditions or mycorrhizae in order
to grow, or if it can even produce viable seeds. All I know is that it
sometimes flowers for me but I have never obtained any Vietnamese
coriander seeds.
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Vietnamese Coriander Flowers |
Vietnamese
coriander is very easy to propagate from cuttings, one of the easiest I
have ever grown. Roots will grow quickly from any node that is under
water, as
long as at least one node is under water then it will grow roots. Roots will only grow from a node, unlike herbs such as basil the roots will not grow from the stem.
I
normally cut a section off the plant, remove the leaves from the lower
few nodes, and then place it in water with the remaining leaves in the
air and the leafless nodes under the water.
I normally remove leaves from several nodes as I am using them in my
dinner, the parent plant you cut pieces off should regrow as long as you
leave it with at least one node that has leaves. If you do not remove
the leaves from your cutting it will still
grow roots quickly, but you run the risk that the leaves may possibly
rot.
I have even seen Vietnamese coriander grown underwater in an
aquarium once. Short term this will work well and the plant will grow
roots from every node, but I think that longer term
this plant needs its leaves out of the water. I really should
experiment with this and see what it is capable of. I would be hesitant
to grow it using aquaponics in fear that it would take over and clog
things pretty quickly.
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Vietnamese Coriander Flowering |
What does Vietnamese coriander taste like
I don’t know how to
describe how things taste but I am rather fond of this one. Some people
say it smells much
like coriander, some think it smells nothing like coriander, I think it
does smell a bit like coriander. Some people claim it smells like
mint, I don’t see how anyone could ever think it smells even slightly
minty and the word ‘mint’ in one of its common
names probably refers to the aggressive growth. Some say it is warm
and peppery, others say citrusy, others disagree completely. The
internet says Vietnamese coriander has a “lovely coriander taste with a
clear citrus note; refreshing with a hot, biting,
peppery after taste” which I think is a reasonably accurate
description.
Vietnamese
coriander is used in many
dishes, as one of the common names suggests it is rather popular in
laksa. I like to put some leaves in my bowl and then pour in hot
chicken soup. The heat from the soup is enough to cook this herb and
make it soft. I think overcooking would make it lose
much of its taste. It goes well with chicken and I am told that it
combines well with lime, chillies, garlic, ginger and lemon grass.
I
don’t eat this herb raw myself as I find it slightly bitter, but have
been told that it works well raw chopped into salads. I really should try this one day and see if I like it.
Unlike
coriander which some people love and others have a broken gene which
makes it smell soapy to them, Vietnamese coriander does not appear to
elicit the same
extreme response from people. That being said, this herb is not for
everyone. I really like the taste and smell of Vietnamese coriander, my
wife dislikes it, some of my kids like it and the others are
indifferent to it.
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Vietnamese Coriander - more sunlight makes the purple more pronounced |
Where to buy Vietnamese coriander in Australia
Some online places sell Vietnamese coriander, and some nurseries occasionally stock it, but prices vary quite a lot and it is usually far more expensive than it should be. The best thing about this plant is that it is perennial so you plant once and harvest forever.
I sell Vietnamese coriander plants or rooted cuttings, when available they can be found on my
for sale page.
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Vietnamese Coriander Rooting Cuttings ready to plant |