Seaweed, sometimes called “hayball” or “bushball”, is immortalized on the big screen in scenes of desert, dry, sandy and rocky plains, seaweed and perhaps the odd “cowboy cactus” (so named because it appears to have his hands are raised). obediently growing upward from the sides) decorating the stage. A barren, dusty area where horse and rider trudge along a boulder-strewn path, probably in search of water.

I have a terrible vision of southern Portugal turning into a similar scenario if we don’t get decent rain soon – we’ll have to deal with both climate change and water shortages as temperatures rise and water levels fall. The land could be cleared of sand and rocks, plants could die, people could start moving north, and here it would be a barren location for yet another Wild West movie scenario. Maybe not next week, but in the distant future. But by the time this article goes to press, there may be more rain than we can handle!

It’s just my imagination working overtime, but the algae you see floating across the American plains are actually real plants, or were before they started rolling haphazardly across the inhospitable landscape.

How did the tumbleweed get there?

The truth about weeds is not simple. Although tumbleweeds are a symbol of the Wild West, they are an invasive weed called Russian thistle, and many modern Westerners fear they are taking over.

Like many invasive species, the plucky Bermuda grass hitchhiked with unsuspecting travelers. In 1873, Russian immigrants arrived in South Dakota, bringing with them flaxseed apparently contaminated with Russian thistle (Salsola tragus) seeds. Once seeded, these invaders grew quickly, unhampered by natural predators and diseases that kept them in check. Every winter, after Russian thistle plants die, the fragile bushy parts break away from the roots and fall off, scattering seeds wherever they fall—a whopping estimate of about 250,000 per plant. Bouncing and rolling in the wind, Russian thistle scatters its seeds so they all get the sunlight and space they need. In fact, it’s not just a noxious weed, it’s a weed that can take over entire neighborhoods, clustering against walls and fences, becoming a hazard to motorists on the roads and a real nuisance to farmers.

Because it requires little water, it was able to quickly establish itself in the vast agricultural fields and overgrazed lands of the American West. By the late 1800s, this intruder had already crossed much of the western states and Canada, carried by wind and even railroad cars.

Credits: Unsplash; Author: @brice_cooper18;

Tumbleweeds were real plants

We rarely think about these living shrubs that could be called beautiful: they have purple-red striped stems, delicate leaves and delicate flowers. They grow from 15 cm to over 90 cm in height and later develop sharp spines. A microscopic layer of cells at the base of the plant, called the cascading layer, allows for a clean break, and the plants happily roll away, scattering seeds as they go.

Ironically, many species of animals and birds feed on the succulent new growth, and Russian thistle hay saved livestock from starvation during the Dust Bowl of the 1930s when other food was available.

But the downside to Russian thistle is that it never stops spreading. Almost the entire United States is home to Russian thistle, as well as several new species of wheatgrass that arrived as immigrants from around the world.

The ongoing drought in the West is a particular boon for these ubiquitous predators, which have caused spiky balls to explode everywhere. A new species of thistle, Salsola ryanii, has been named “monster thistle.” Although scientists thought they would go extinct, they are actually expanding and causing even greater problems in many areas: being a hybrid of two other types of algae, they grow more vigorously and can reach heights of over 180cm.

Let’s hope they don’t take root here.