How come tumbleweeds, which are the public’s nightmare and have put the United States into a state of emergency, are considered a delicacy by us?

In 2014, two cities in Colorado declared states of emergency due to tumbleweeds.

In January 2020, a large number of tumbleweeds appeared on SR 240, more than 30 kilometers west of West Richland, Washington. These hundreds of tumbleweeds not only blocked the road ahead, but also buried a large truck under a 4.5-meter-high pile of weeds.

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It looks really miserable. Image source: Twitter

Every fall and winter, a large number of grass balls appear out of nowhere on the plains of the Midwest of the United States. They not only roll and "jump", but also gather in groups. Although they look a little funny and cute from a distance, they are not so easy to get along with. Most Americans hate this "troublemaker".

Tumbleweeds are actually a general term for plants that can roll with the wind after drying. Most of the tumbleweeds that are rampant in the Midwest of the United States and are its iconic "landscape" are a plant called Kali tragus , which belongs to the genus Salsola in the Amaranthaceae family and is native to Russia, Austria, Germany, Qinghai and Tibet in China.

The next superhero movie might be called "Fighting Tumbleweeds." Image source: YouTube

‍Tumbleweed didn’t originally look like this. It was once lush and green, and even had small white flowers. Many animals feed on the juicy young shoots of A. spinulosa, including mule deer, pronghorn antelope, woodchucks, and birds. And during the Dust Bowl in some areas in the 1930s, A. spinulosa was used as feed to keep cattle from starving because there was no other feed available.

But in autumn, when everything begins to wither and die, it naturally cannot escape death. Its branches begin to dry up, and the part above the ground is also disconnected from the underground rhizome. As long as the wind blows, the tumbleweed, which has no roots and loves to wander by nature, begins its journey.

White and tender, how old are you now? ! Image source: wiki

The United States is not in the native range of the thorny sand sedge, so why is it so rampant? In fact, the thorny sand sedge is an invasive alien species in the United States.

In the 1870s, when the United States imported flax seeds from Russia, it accidentally brought the tumbleweed into the country. The newly arrived tumbleweed was very reserved at first, and there was no intention or sign of "dominating the world", so the local people did not pay much attention to it. But the good times did not last long. After only 20 or 30 years, the tumbleweed began to spread like a disaster. Today, this plant has been found in all states except Alaska and Florida.

The locals are finding joy in the midst of hardship. The picture comes from the Internet

The reason lies in the strong reproductive ability and environmental adaptability of the spinulosa. A spinulosa plant can carry about 200,000 seeds . When they roll, the violent rolling will help it shake out the seeds. When the time is right, these seeds scattered on the ground will grow into new spinulosa plants, and the cycle will repeat. In addition, because they have a low demand for water and have a good tolerance to salinity, their growth environment is rarely restricted and they can grow freely along the beach, in grasslands and in the Gobi Desert.

Sowing seeds like this. Image credit: tenor‍

In addition, the United States has a relatively flat terrain , with plains accounting for half of the country's land area, and the plains have good ventilation conditions . This provides a favorable terrain for the movement of tumbleweeds: not only are there no obstacles, but the wind is also relatively strong. With the help of wind, tumbleweeds are like a bouncing wheel, rolling and jumping, and can even move more than ten kilometers a day , constantly expanding the population range.

They really look like two conscious creatures (? Image source: YouTube

The tough, thorny plant can clog irrigation ditches and spread pests. The tangle of dry branches that tumbleweeds are particularly flammable, posing a threat to human life if it catches fire when it rolls across a fire line or accumulates on structures such as homes.

Tumbleweed Survival: Savage Invasion. Image source: YouTube‍‍

The rampant tumbleweeds often invade roads and streets, and residents in the Midwest of the United States either wake up to find their doors blocked, their houses buried, or their cars buried. Encountering an invading tumbleweed on the road is likely to block the driver's vision and cause a traffic accident.

Come and feel the shock of tumbleweeds! Image source: tenor

Shock +11111 Image source: YouTube‍‍‍‍‍

Many measures have been taken against P. spinulosa and other tumbleweed species, including pesticides, cutting down seedlings or pulling them out before seeds have a chance to develop, and large-scale burning, but these methods are often expensive and time-consuming.

The USDA is also testing specific natural enemy insects and viruses imported from Russia, the plant’s primary homeland. In 2014, the ARS announced the discovery of two promising fungal pathogens, Suromyces salsolae and Colletotrichum salsolae, that could infect and kill tumbleweeds.

Image source: tenor

There are two reasons why tumbleweeds have not become a disaster in China. First, it is a native species and part of the ecosystem, and has natural enemies that can curb its excessive growth. In addition, China is mostly mountainous and hilly, with undulating terrain , which is not conducive to the rolling and spreading of tumbleweed seeds.

Salsola. Image source: Plants of World Online

As for the saying that "the tumbleweeds did not spread because we ate them all", this is actually a rumor!

The Amaranthaceae family, from which tumbleweeds come, is rich in food, and the most well-known ones are amaranth and spinach. The young leaves of Amaranthus spinulosa are indeed edible, but what people eat a lot is actually Salsola, which looks similar to it and belongs to the genus Salsola in the Amaranthaceae family.

This often leads some people to mistakenly believe that they are eating Bushy Bush and are saving the world (bushi).

References

[1]https://www.usatoday.com/story/news/nation/2020/01/01/tumbleweeds-bury-cars-drivers-washington-state/2792122001/

[2]https://agresearchmag.ars.usda.gov/2014/sep/weed

[3]https://www.treehugger.com/everything-you-ever-wanted-know-about-tumbleweeds-4864166

[4]https://bie.ala.org.au/species/https://biodiversity.org.au/afd/taxa/f32becff-d994-4673-803b-1d58cce32130

Planning and production

Source: Bringing Science Home (id: steamforkids)

Author: Ah Xian Editor of "Everything" magazine

Editor: Yang Yaping