Poison behind the petals: Parthenium creeps into floral garlands
Experts warn that contact with parthenium can cause allergies, asthma, respiratory distress and severe skin problems in humans. For livestock, consuming it may even prove fatal
Highlights:
- Toxic parthenium weed is being sold in flower bouquets nationwide
- Contact causes skin irritation, asthma, and severe allergic reactions
- Sellers use parthenium as a cheap substitute for costly flowers
- The weed has spread to over 45 districts, harming crops
- Despite bans, parthenium remains widely sold in markets
- Experts urge stronger regulation, research, and public awareness campaigns
Flower bouquets and garlands are a common part of celebrations, receptions and festive occasions. But hidden behind their beauty is a dangerous intruder – the toxic weed parthenium, now being sold freely in flower shops across the country.
Experts warn that contact with parthenium can cause allergies, asthma, respiratory distress and severe skin problems in humans. For livestock, consuming it may even prove fatal.
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Recent visits to the capital's two main wholesale flower markets – Shahbagh and Agargaon – found roses, marigolds, jasmine, tuberose, and lotus arranged beautifully alongside parthenium. Bouquets and garlands were being made with it. Sellers said that while flowers like gypsy, golden stick, and limonia are typically used to enhance appearance, they are costly. So, shopkeepers often use parthenium, which looks similar but is far cheaper. The bushy weed, also known as "Congress grass," grows abundantly along roadsides and rail tracks.
Although there has been little research on parthenium in Bangladesh, a study in Ethiopia found that 90% of farmers exposed to the plant suffered allergic reactions, 62% developed asthma-like symptoms such as coughing and breathing difficulties, and 22% experienced stomach pain after inhaling its pollen.
Dr Md Elias Hossain, chief scientific officer at the Bangladesh Wheat and Maize Research Institute, who has been studying parthenium since 2008, told The Business Standard, "Our research shows that contact with parthenium initially causes itching and skin irritation, which can develop into eczema. It can also lead to respiratory problems, bronchitis and asthma."
On its use as a decorative flower, he said, "Allergies have become common nowadays, and people often don't know the real cause. This demands extensive research. Using parthenium as a flower is alarming – the government must monitor the situation and raise awareness."
How parthenium entered the flower market
Sabikun Nahar Tonni bought a bouquet and floral headpiece from the Shahbagh market – made of roses, marigolds and jasmine – only to find they contained parthenium, which vendors falsely called "gypsy".
"I always thought it was gypsy," she told TBS. "If it's actually parthenium, that's horrifying. How can ordinary people tell the difference? This is deception."
Flower sellers said most decorative flowers are imported, and taxes and duties push import costs to Tk1,000–15,000 per kg. A small handful of gypsy flowers costs Tk400–500, whereas the same amount of parthenium costs only Tk10–20. This steep price gap encourages sellers to use the toxic weed in garlands and bouquets.
Shahbagh flower vendor Md Mahbub Hossain said, "I've heard it's harmful — it causes itching if it touches the skin. But since gypsy is expensive, people still want this. That's why we sell it."
Early on Saturday morning, several vendors were found sitting along the main Shahbagh road with heaps of parthenium for sale. One of them, Siya Ram, said he collects the weed daily from beside the Tongi railway line and sells a handful for Tk100. "People buy it. I sell Tk800–1,000 worth every day. They say it's harmful, but nothing's happened to me," he said.
Because of its health risks, the Agargaon Flower Market Traders' Association banned parthenium sales in June. However, after brief enforcement, it has returned to the market – freely sold in roadside shops once again.
Association president and Bangladesh Flower Association general secretary Imam Hossain told TBS, "In our main market, parthenium is banned and no member sells it. Many sold it earlier because they didn't know how harmful it was. But shops outside our market still do – mainly because it looks like gypsy and costs less."
How the invasive weed spread across Bangladesh
A recent study titled "Distribution and Management of Parthenium Weed: A Risk and Threat to Food Security under Changing Climate in Bangladesh" revealed that Parthenium hysterophorus, an invasive species from Mexico, is spreading rapidly and threatening food security. First identified in Jashore in 2008, it now infests more than 45 districts, with dense growth in Rajshahi, Chapainawabganj, Jashore and Mymensingh. It grows along roadsides, fallow lands and crop fields, affecting at least 25 crops, including wheat, maize, pulses, vegetables, spices, banana, potato and sugarcane.
Researchers found that its toxic compounds reduce seed germination, pollination and crop yields, while also causing skin disease, asthma and ulcers in livestock. The infestation is most severe near the Indian border. Weed-control trials showed that herbicides such as glyphosate, and its mixtures with atrazine or tembotrione, can suppress 69–74% of young plants — though less effective later and environmentally risky.
Dr Elias Hossain, who led the research team, said the weed likely spread via the tyres of goods trucks from India. "A single parthenium plant can produce 60,000 to 1,00,000 seeds, which can disperse up to 6 kilometres by wind," he said. "Crop yields can drop by as much as 40% once it invades farmland. Initially, it was seen in border areas, but now it's everywhere."
Researchers noted that parthenium has been declared a weed of national importance in countries like Australia, India, Sri Lanka and South Africa. They urged that Bangladesh recognise its growing threat at both policymaking and farmer levels.
Abdul Rehman, deputy director of projects implementation and research at the Centre for Agricultural Bioscience International (CABI), stressed both short- and long-term control measures. "Public awareness, manual removal, and biological control can help contain its spread in the short term. For the long term, integrated management combining chemical, biological, and cultural methods backed by strong policy is essential," he told The Business Standard.
He added that countries like Australia and India have implemented successful biocontrol programmes that Bangladesh could adapt. "Farmers, communities, and the media have vital roles in early detection and spreading awareness to prevent parthenium's spread," Rehman said.
Bangladesh Flower Association organising secretary Zahir Uddin Md Babor said, "Since 2023, parthenium has been widely used in floral garlands and bouquets. After learning about its dangers, our association banned it and ran awareness campaigns. Our members no longer use parthenium, but we cannot control non-member sellers. The government must monitor the market and increase public awareness."
Dr Farzana Nasreen Khan, chief scientific officer of the flower division at BARI, said, "We include parthenium awareness in our training programmes. But there should be widespread campaigns highlighting its harmful effects. Once people are aware, no one will dare to sell it."
