Mentha australis - native river mint

A number of years ago I found a small herb for sale that was labelled as: native river mint - Mentha australis. There are about 25 species and countless interspecific hybrids and varieties of mint (Mentha), only about six species are endemic to Australia.

I had always heard that there were a few species of mint native to the area I lived, I spent much of my life outside in the bush and have looked for them but I had never actually seen one in the wild.

This native river mint plant was small, it had long thin wiry stems, it only had a few leaves and they were all rather small. Overall this plant looked pretty weak. I smelled one of the leaves and it smelled strongly like peppermint. That was enough to make me try growing native river mint.

I bought this plant and excitedly took it home that day. I did some research and it appears to be correctly labelled. Even though I had never seen one in the wild it is indeed one of the species that is, or at least was, native to my area. Who knows, perhaps these are locally extinct in the wild now.

Typical stems of native river mint

From what I read this plant used to be really common and was used as bush tucker or medicine as well as food for the first Europeans. Native river mint is pretty rare in the bush now, it is said to persist as seeds in the soil on ephemeral flood plains where it springs up after rains and may be lucky to flower and drop seed before it is grazed to death. I still hope to see it growing in the wild near a stream one day and I plan to take a small cutting if it is growing where that is allowed.

I grew my plant in a pot sitting in some water, many types of mint have huge weed potential as they spread by underground runners as well as drop masses of incredibly tiny seeds. Mine grew rather well as an emergent water plant with the roots in water and the leaves in the air, it grew far better as a normal terrestrial plant that is never submerged and is just watered infrequently. Like most types of mint, this needs a bit of water to really flourish. Native river mint does spread by runners, and it does set tiny little seeds, but it doesn’t seem to spread very far by itself and doesn’t appear to pose a weed threat. While I don’t have any seedlings from seed fall I assume the seeds are viable. Perhaps it may need a second (genetically different) plant in order to set seed, but I doubt it.

Native river mint is a civilised variety of mint that is simple to contain and if you put in some work can actually be grown in the garden without it taking over. You can’t honestly say that about many varieties of mint!

Native river mint leaves - front and back

Based on what I have seen from growing this for a few years I can say that native river mint always has long thin stems, and always has small leaves, this appears to be its normal growth habit. The small leaves smell and taste very strongly of peppermint, and are simple to strip from the stems for use. My plant always has leaves and does not appear overly bothered by heavy frosts.

I assume it is very healthy to eat but have no evidence of this. My kids enjoy herbal tea made from native river mint and sometimes they mix different herbs together. I grow a lot of different herbs and things so they have plenty of choice.

I have never tried to collect/grow its seed so can’t comment on how easy they germinate or how much diversity they have from seed or even if one plant can set seed without cross pollinating.

Native river mint is native to my area, which means that if its seed ever gets into bush land it will actually be a good thing and it won't be adding to the weed burden in the area.

These grow very easily from cuttings, I take cuttings of this when I remember and they root easily in moist soil or even in a glass of water.

Mentha australis cuttings ready to plant

Native river mint flowers for me each year and feeds several species of native bees and other native insect pollinators. They possibly also feed honey bees but I have yet to see them working its flowers, which means it is not their preferred source of food so the native bees get a greater share of its nectar and pollen resources.

Many of our country’s native bees and other insect pollinators are becoming increasingly rare. I don’t know if this is due to competition by introduced honey bees, or lack of suitable foods due to land being cleared for housing/crops, or lack of appropriate nest sites, or wide scale pesticide use, or any number of factors. Many of the native plants people grow are not native to this area and have larger flowers and are very attractive to honey bees. Growing small flowering native plants such as native river mint provides suitable food for native insects and may give them a competitive advantage over the larger and more aggressive honey bees. By growing organically you are not adding to the pressures these native insects face from wide scale pesticide use.

Perhaps growing small native plants like this organically will help the local ecology in a small way. If enough people in an area grew one or two things like this I think it would make a big difference. Native river mint is a useful edible herb that is easy to grow and doesn’t pose a weed threat, which in itself makes them worth growing. If growing native mint helps the local ecology in some way then that is an added bonus.

Native river mint is simple to grow, is good to eat, is good for the environment, but can be difficult to find for sale because few people know about it. I sell native river mint plants through my for sale page and can post it to much of Australia.