Vietnamese coriander flowering

Vietnamese coriander (Persicaria odorata) is an edible perennial herb from south east Asia.  I wrote an earlier post with Vietnamese coriander growing notes.  This is a very simple to grow, productive, and great tasting edible herb.  This is not related to coriander in any way, but can often be used in a similar way.

Vietnamese coriander loves heat, humidity, water, yet strangely does not appear to like full sun all day (although this may just be in my climate where humidity is too low).  For me leaf production is best when it gets part shade.  This is easy to provide by growing it next to something taller.  

I often grow it in a container with no drainage holes, I have soil or leaf litter in the bottom, and a few cm of water on top of the soil.  I have grown it in a pot of soil, where it does well.  I have also seen people grow this in their vegetable garden.

I have always been told that this plant will not flower outside the tropics, but that is not true.

I first got Vietnamese coriander when I lived in semi-arid central west NSW, and it flowered there.  Now that I live near Canberra with its hot dry summers and cold winters (cold by Australian standards) it still flowers.  Most years I don't get many flowers from this plant.

This past year the weather was odd, it was mild and wet all summer.  My Vietnamese coriander flowered more than it ever has before!

Vietnamese coriander flowers

The flowers appear at the end of the growing stalks.  Many flowers are on each stem, they open sequentially from the base up to the tip.  The flowers don't really smell, or if they do I could not smell them over the foliage.  Flowers last a few days before dropping off.

Unlike many other herbs, the leaves do not appear to turn bitter or have any off flavours when flowering.  I haven't tried eating the flowers so don't know what they taste like.

Vietnamese coriander flowering

I have never seen any seed set.  I m not sure if it needs another clone to be able to cross pollinate, or if it in unable to set seed, or if my climate is all wrong for seed production, or if we do not have the right pollinators, or if there is some other issue at play.

I have had this plant for many years now, it grows so easily from cuttings.  Vietnamese coriander always grows prolifically for me, and produces many large leaves.  As such I don't need any true seed to be formed.

For me these grow best in spring, summer, and autumn.  My plants don't love frost, and growth slows during cold weather.  

I am growing some outside where it gets lighter frosts, these plants have reddish leaves over winter that are small, bitter, and not really worth eating until the warmer weather returns.  Once the weather warms they grow greener leaves that have no bitterness.

I grow some in my unheated greenhouse, the leaves of these are green and lush all winter and all year.   At this time of year they lose the arrow shaped markings on their leaves as the sun is not strong enough.  That doesn't bother me, they still taste great.

I also have some growing outside in my goldfish barrelponics, this is lush productive all year long.  The ones in the barrelponics has by far the most explosive growth and is not even slightly bothered by winter as the barrel water must keep it slightly warmer.  Over summer it can suffer slightly from direct sun, but there is always some that gets enough shade that it is still fast growing and great to eat.  Between this and water cress the goldfish water stays clear and clean.

If you don't grow Vietnamese coriander you should.  Sometimes plant nurseries carry them, but it seems to be a bit hit and miss.  I also sell organically grown plants of these through my for sale page.