June 21, 2024

The Hidden History of Weeds

Maligned as a pest and otherwise ignored, weedy plants often have fascinating backstories. This is, the hidden history of weeds.

Banyule Flats: a have for weedy plants
Banyule Flats: a haven for weedy plants

I recently read an article in the New Yorker called ‘What is a Weed?’ by Rivka Galchen. This provided an interesting perspective on these overlooked plants; that they often have long histories, a variety of uses, and different guises, depending on the observer.

Their relationship with humans is complex. As Galchen puts it, certain weeds have a backstory of almost Shakesperean proportions, with a rise and fall; promoted for one reason or another, then viciously eradicated when we decide they are no longer useful.

Many human figures from history could relate.

Of course, many weeds are pests, and may be harming the environment they are in. But it still serves as a reminder: the everyday things that you see, on closer examination, are almost always interesting.

So on my walk last Sunday I thought I would identify a few weeds that I saw, and look into their histories. The location was Banyule Flats, in Melbourne’s northern suburbs, my tool was the plant identification app ‘PlantNet’ (which I highly recommend).

And the weeds? All of them ordinary, until they were seen to be not. Here are a few highlights.

Marsh Pepper Smartweed

Marsh Pepper Smartweed

My walk took me around Banyule Lake, and there was a lot of this, growing on the swampy shoreline. The Marsh Pepper is a squat, robust plant, with narrow, leathery leaves; at first glance it is inconsequential, and not overly appealing.

The scientific name is Persicaria Hydropiper. Like a lot of weedy plants it is also has a host of colloquial names: Smart Pepper, Water Pepper, Marsh Weed, and Knot Weed.

Marsh Pepper is found all over the world, and is considered native to Africa, Southern and Central Europe, Central Asia and Australia. This suggests the species is old, and evolved at a time when these areas were directly connected. It also indicates it is  adaptable; while it likes plenty of water it is otherwise not that particular, and can grow in a variety of soils and climates.

The Marsh Pepper is closely related to a Vietnamese plant known as Rau Ram-a, which is extensively used in that country’s cuisine. While it has not been a traditional ingredient itself, it was not hard to find an enthusiastic online community, championing its virtues:

‘If you’re a forager who likes spicy food, prepare to fall in love with Marsh Waterpepper. Eat a leaf raw and you’ll get a kick just like you bit into a chilli pepper.’


– ‘Forager Chef’, blog

There are many websites with recipes, and tips on harvesting and preparation.

Warty Bedstraw

Warty Bedstraw

Growing amongst a clump of trees next to a sports oval carpark was this bright green, delicate looking plant. It had small leaves in a star pattern, of the type that causes them to stick to your clothes if you brush past them.

Native to North America, Warty Bedstraw was heavily utilised in frontier times. The leaves of the plant are edible, settlers ate them as a side dish; they also boiled them in water to produce a coffee substitute (the plant is from the same family as coffee, Coffea spp.).

They also thought the plant had medicinal properties, and used it as a treatment for headaches, menstrual cramps, and infections. Modern research has revealed the plant has no real medical value, but the settlers may have benefited from a kind of placebo effect.

They also provided the plant’s name. While sticky, the plant does not compress well, which made it an ideal material to use as a mattress filler.

Patience Dock

Patience Dock

Dotted along the path at regular intervals was a plant that looked a little like a Romaine Lettuce: broad, long green leaves with a prominent spine, growing from a central clump. This proved to be Patience Dock, a plant that did in fact serve as a common salad green, for hundreds of years.

Native to central and southern Europe, in classical times this was a dinner staple in Italy, Greece and Spain. In the 16th century it was introduced to England, which may explain the unusual name: some researchers think the Italian name, ‘Lapazio’, may have been incorrectly rendered into English as ‘Patience’.

In that country it was also known as ‘Monk’s Rhubarb’: easy to grow, it was a common vegetable found in monastery gardens. Its use in England began to decline in the 19th century, although exactly why is unclear; Patience Dock has a mild flavour, it may simply have been supplanted by leafy greens with a stronger taste.

While much less popular than in earlier times, it is still consumed in southern Europe.

History of Weeds: Milk Thistle

Milk Thistle

One of the commonest plants I saw on my walk was one of the few I could attempt to identify without ‘PlantNet’; a stalky plant with pointy leaves and white prickles, I guessed this was some kind of thistle. And I was right, my app confirmed it as ‘Milk Thistle’ (aka: Silybum marianum).

Originally from North Africa, Milk Thistle spread through the Mediterranean, where it was widely used as a medicine. A white liquid can be derived from the plant, which provides its common name, in classical times this was thought to be restorative.

It was prescribed to treat liver conditions, and to promote general health.

In the Christian era this white liquid came to be associated with the Virgin Mary. Seen as a type of mother’s milk, this provided the plant with a number of new names: Blessed Thistle, Holy Thistle, and Saint Mary’s Thistle among them.

This sacred connection caused the plant to be viewed as almost supernatural, and it was used to treat a large number of maladies: indigestion, jaundice, gallstones, and to cure insect bites, snake bites, and mushroom poisoning.

It seems that if an illness had no treatment, you could at least try Milk Thistle.

Milk Thistle, modern format
Milk Thistle, modern format

In the modern era, most of these medical claims have been debunked. But Milk Thistle extract is still sold, and promoted usually as a means to improve liver health, much as it was thousands of years ago.

And some recent research does suggest that Milk Thistle may be a useful treatment for Cirrhosis of the liver, as well as Hepatitis C. Different studies have produced conflicting results, some positive, the research continues.

History of Weeds: Egyptian Mallow

Egyptian Mallow

Another plant I saw throughout the park was this small, low growing specimen, that looked almost like a weed stereotype: plain, insubstantial, with roundish leaves atop thin stems. This turned out to be Egyptian Mallow, one of the most versatile plants I came across.

Hailing originally from Egypt – and so one of the few weeds that are accurately named – different parts of the plant were used in different aspects of traditional medicine. The leaves were eaten to help with digestive and urinary tract problems; ground up they were turned into a poultice, to treat rashes and other skin problems.

It was also boiled and served as tea, which was used to treat anxiety.

Cheeseweed Fruit
Cheeseweed Fruit

The plant produces small, nutlike fruit that have a savoury flavour. These can be eaten as a snack, and have given rise to its other colloquial name: Cheeseweed.

It has other ecological benefits as well:

‘Cheeseweed Mallow’s small, year-round blossoms are like a beacon for bees, butterflies, and moths; the plant’s continuous flowering ensures these crucial garden allies have a consistent food source. The roots dive deep, breaking up compacted soil and making room for water and nutrients. This improves soil structure but also helps prevent erosion.’


–  ‘Cheeseweed Mallow Uses’, blog

This useful plant is highly adaptable and surprisingly hardy, and is now found throughout the world.

Cosmos Caudatus Cunth


An attractive, flowering plant with an evocative name is Cosmos; actually, ‘Cosmos Caudatus Cunth’, a tall, grass-like plant crowned with pale violet and yellow flowers. There was a big patch of this at one point of my walk, I did not see it otherwise.

Native to Central America, Cosmos was brought from there to the Philippines by Spanish conquistadors. It then spread throughout south-east Asia, and became prominent in several local cuisine styles.

Cosmos flowers
Cosmos flowers

In Indonesia it is called ‘Kenikir’ and is a common green used in side dishes and salads. In Malaysia it is known as ‘Ulam Raja’, and is served in a preparation called ‘The King’s Salad’. And in Brunei it is mixed with Sambal and served as a side accompanying the national dish, a starchy, savoury, tapioca-like item called ‘Ambuyat’.

In these and other countries of the region it is widely consumed, and found in cafes, restaurants, and people’s homes. It is not much eaten outside of southeast Asia.

History of Weeds: Jerusalem Cherry

Jerusalem Cherry

After a while I diverted off the main path, and walked along a dirt track beside a stretch of the Yarra River. This was a quiet area: the water level was low and the river completely still, there was no breeze at all. Bush birds called out in the trees above, the understory was thick with vegetation.

I only saw one other person on this track, an older bloke walking their dog.

To the left of the path at one point was a stout, dense bush with small red fruit; this turned out to be Jerusalem Cherry. Native to Ecuador and Peru, it had been brought to Europe in the 16th century by Portuguese traders.

Decorative Jerusalem Cherry
Decorative Jerusalem Cherry

The leaves of the plant are dark green and the fruit brightly coloured, this striking combination made it popular as a decorative ornament; in the Late Middle Ages, Jerusalem Cherries were found in home and gardens across Europe. Despite their pleasant appearance, the fruit are poisonous: if consumed they can cause sweating, nausea, and gastric distress (although they are not fatal).

How they got their distinctive name is not known.

‘The name is a misnomer, as the plant does not bear real cherries and is not native to Jerusalem. One hypothesis is that ‘Jerusalem’ is a substitute for a foreign or exotic country when the plant’s namer doesn’t have a background to attribute.’


– The Georgia Gardner, blog

Another example of this is the ‘Jerusalem Artichoke’, also not from Jerusalem.

Like all the plants I saw, this had been on a journey that is fascinating to think about: from Ecuador, to Medieval Portugal, to Jerusalem and then gardens across the continent. And from there to colonial Australia, and somehow to Melbourne, and somehow to this forgotten spot on a less trafficked path beside the Yarra River.

There was only one example of the Jerusalem Cherry in sight. Growing on its own it was thriving, surrounded by the other weeds.


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