- Karnataka is the latest state to issue an advisory on planting Conocarpus trees, following prohibitory orders by the state governments of Gujarat, Telangana, Andhra Pradesh, and Tamil Nadu.
- While their fast-growing, drought- and salinity-tolerant nature makes them attractive to greening initiatives in India, Conocarpus poses significant ecological concerns that warrant caution, ecologists said.
- Even though Conocarpus trees have no formal invasive alien species status in India, they should at least be treated as ‘emerging invaders’, according to invasive biologists.
In March, the Karnataka High Court directed the Greater Bengaluru Authority (GBA) to consider the issues highlighted in a public interest litigation (PIL) petition seeking the removal of all Conocarpus trees planted across the city.
The high court advisory on Conocarpus, a genus of trees introduced to India from the Gulf, where it has been extensively used in urban landscaping, comes on the heels of prohibitory orders enforced by the state governments of Gujarat, Telangana, Andhra Pradesh, and Tamil Nadu.
In August, 2025, based on a report by the Central Empowered Committee (CEC), the Government of India issued a national advisory to all states and union territories to stop the plantation of Conocarpus erectus (buttonwood) and Conocarpus lancifolius (damask) with immediate effect, flagging ecological and public health concerns. The report compared the Conocarpus species with invasive plants such as Lantana camara and Parthenium hysteroporus.
How did Conocarpus take over urban India?
There are two species of Conocarpus trees found in India, Conocarpus erectus and Conocarpus lancifolius. Of these, Plants of the World Online (POWO), a global digital database of the world’s flora, only recognises the introduction of Conocarpus erectus to the country. However, Achyut Banerjee, a plant invasion biologist and assistant professor at Azim Premji University, Bhopal, says both species, including Conocarpus lancifolius, followed a similar route into the country. “They were brought from their native range to Gulf countries for urban landscaping, and then introduced to India from there,” he said.
Over the past decade, Conocarpus has mushroomed in different parts of India through plantations by private and public entities.
It was in late 2016 that Dipani Sutaria, founder of Ujaar, an Ahmedabad-based restoration organisation, first noticed Conocarpus trees in her city. “There were suddenly these trees that looked like misfits in the dry, arid landscape of Ahmedabad,” Sutaria said. By 2020, they had become even more predominant in the newly expanding sections of Gujarat’s largest city, the ecologist added.
Spaces that were once occupied by native species such as Salvadora persica (jhar in Gujarati), Salvadora oleoides, Manilkara hexandra (palai in Tamil), Capparis sepiaria, Albizia lebbeck (siris tree), among many others, were now replaced by a monoculture of Conocarpus, according to Sutaria. “I know this because I have seen the loss of these native trees and the dominance of Conocarpus in the rural and peri-urban areas [of Ahmedabad] for the past six years,” she said.
According to Sutaria, by 2020, Conocarpus had become a prominent feature in the newly expanding sections of Gujarat’s largest city. They were planted alongside roads and boundary walls in large numbers, the ecologist said.
Meanwhile, down south, in Telangana, Conocarpus became popular in greening efforts by citizens.
Launched in July 2015 by former chief minister Kalvakuntla Chandrashekar Rao, Telangana Ku Haritha Haram (a green garland for Telangana) was a flagship afforestation program aimed at increasing the state’s green cover from 24% to 33%.
The program involved people from all walks of life, said Mohan Pargaien, a retired Indian Forest Service (IFS) officer, who served as the PCCF & Chief Wildlife Warden for Telangana. Municipalities and panchayats had set targets, not just to plant saplings, but also to ensure their survival.
In that scenario, local governing bodies started using Conocarpus saplings for the afforestation drives. “Once people realised their potential as a fast-growing species that demanded little maintenance, they spread from village to village and were planted year on year,” he said.
The species was already being used for greening in Gujarat, and he believes that is how it eventually reached Telangana. “It was not part of any government decision, and they were never raised in government nurseries. It was truly a people’s movement,” the former IFS officer added.
According to Banerjee, Conocarpus trees have all the traits that make them attractive for greening. “Tree plantation drives in India have always faced a shortage of funds for nurturing saplings, their maintenance and protection,” Banerjee said. “A low-maintenance, fast-growing, drought-and-salinity-tolerant species like Conocarpus is structurally attractive for greening targets.”
What is the species status in India?
While Conocarpus erectus is native to Central and South America, along with coastal sites in southern Florida and the west coast of Africa, Conocarpus lancifolius is native to and restricted to the seasonal rivers and coastal sites around the Red Sea from Somalia to Yemen, Banerjee said.
But Conocarpus has no formal invasive alien species status in India, according to Banerjee, who runs the Indian Alien Flora Information Database (ILORA). Invasive alien species are non-native species which have been introduced either accidentally or intentionally into native ecosystems, and which outcompete native species to spread aggressively over relatively short periods of time.
Both species have been introduced to India recently, and further studies on their ecological and socio-economic impacts are required, the ecologist said. “The best we can say from global literature is that they should be treated as ‘emerging invaders’,” he added.
The former Telangana PCCF, Pargaien, however, stressed that their resilience and adaptability, and the ease with which they propagate, warrant an invasive tag for both Conocarpus species.
What are the public health and infrastructure concerns?
Apart from their threat to local biodiversity, one of the primary concerns about Conocarpus species is their allergenic pollen. Previous studies from Pakistan and the Middle East have shown that Conocarpus pollen can have an asthmatic impact, Pargaien told Mongabay-India.
A study from southwestern Iran found 58.6% reactivity towards Conocarpus erectus pollen among its test population. The study concluded that the allergenic potential of Conocarpus pollen was high and similar to that of other trees widely cultivated in southern Iran.
However, a closer look at its methodology reveals that the study was conducted on a group of patients with respiratory allergies, such as allergic rhinitis and asthma, from the same allergy clinic. “While it does not mean that the pollen risk is zero,” Banerjee said. “The 58.6% figure from a clinic population with significant allergies should only be interpreted as comparable to several other common ornamental species that we already have in our cities.”
At the same time, another study from southwestern Iran concluded that Conocarpus pollen has a low potential for inducing allergic responses.
“There is no study of [Conocarpus] pollen in India and nor does its environmental prevalence suggest allergenic nature,” according to A. B. Singh, former Associate Director at/or CSIR Institute of Genomics and Integrative Biology, whose research focused on pollen and fungal allergies.
The aggressive root system of Conocarpus is another concern, which, as similar to other plants like peepal, can cause significant infrastructure damage, Pargaein said.
Infrastructure damage is due to poor horticultural planning, according to Banerjee. “The lack of irrigation and failure to prune trees planted near infrastructure are the main causes of damage via hydrotropism, where roots extend in search of water and end in pipe penetration, leading to blockage of water and sewer pipes,” he said.
As a drought-tolerant species, Conocarpus roots naturally seek out subsoil water and use it, reducing the water table, Banerjee said. They are similar to the Eucalyptus, but have unusually vigorous root systems, the biologist added. “It is an adaptation for surviving the unstable, brackish, low-nutrient coastal substrates it evolved for,” he said.
Pargaien also highlighted another aspect of Conocarpus, also commonly found in invasive plants: allelochemicals, a type of compound released by the plant which can hinder the growth and germination of surrounding vegetation. Conocarpus leaves are high in tannins, and once they fall and decay, they affect soil nutrients and other plant roots, according to the former IFS officer. “This is why nothing grows under Conocarpus trees,” he said. Conocarpus trees are often referred to as the ‘green desert’ for this reason.
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What more can we do? Are the bans effective?
With Conocarpus trees, landscapers, horticulturists, and gardeners finally have a solution for the green vertical walls their clients demand, said Sutaria, the Ahmedabad-based restoration practitioner, who bemoans the loss of native trees in her city. “The tree has passed the test [in terms] of the industrialisation of greening,” she said. “They grow straight up, are tall, well-behaved, and follow strict design order,” Sutaria added, explaining why the species is so attractive to landscapers.
Even though the Gujarat government banned the planting of Conocarpus trees in September 2023, they continue to “spread like fire”, Sutaria said.
In Bengaluru, a rapid environmental impact assessment conducted by the School of Climate Change and Sustainability, Azim Premji University, of a proposed metro rail project along a 5.1 km stretch between Nagarbhavi Circle and Sumanahalli Cross found that, among the 652 trees counted, 80 were Conocarpus erectus.
However, Seema Mundoli, one of the authors of the report, insisted that she had not noticed the species in older parts of Bengaluru where there is more diversity of both native and exotic trees.
B.P. Ravi, who serves as the Principal Chief Conservator of Forests (EWPRT & CC) of the Karnataka Forest Department, said he has only seen Conocarpus trees in select urban spaces. While he has spotted the species in a few localities in Bengaluru, he has never come across them in other cities in the state.
Ravi stressed that the state forest department has never raised Conocarpus saplings or advocated their planting on government or public lands. Referring to the Conocarpus saplings planted by the Greater Bengaluru Authority (GBA), the city’s apex civic body, he added that they should be weeded out soon. GBA has stopped planting Conocarpus, and with so much public awareness and media coverage about the species, private nurseries should follow suit, according to the officer.
However, there have been no directives from the state forest department or GBA regarding a ban on planting Conocarpus saplings, so far.
According to Pargaien, the ban has been effective in Telangana, where its spread has been restricted to community lands and along roadsides and road medians. While it is pertinent to recognise its proliferation across urban spaces in the country, it is equally important to acknowledge combative action, Pargaien said. “The kind of awareness that these five states have shown, and the general awareness among the larger public, should mean that [Conocarpus] is not going to proliferate like Prosopis juliflora,” he said.
Banerjee recommends caution, as with other similar species that are being brought to India for ornamental purposes. “A ban is needed until we do a complete risk assessment of both [Conocarpus] species,” he said.
Banner image: Conocarpus erectus saplings. Representative image by TreeWorld Wholesale via Flickr (CC BY 2.0).