Is Ba Vi wild sunflower a strong invasive species?

While some opinions state that wild sunflowers are a strong invasive species, many people still love them and flock to the national park to "hunt for wild sunflowers".

Recently, a post about wild sunflowers by Dr. Dang Hoang Giang on social media has caused a stir among many people. Specifically, Dr. Dang Hoang Giang wrote that "wild sunflowers are a strong invasive species in many tropical countries, including Vietnam". He also cited the opinions of experts that wild sunflowers are one of five invasive species that pose a high risk in the buffer zone, and one of two invasive species that pose a high risk in the core zone of Ba Vi National Park, the other being pentacolor.

Young people take photos with wild sunflowers at Ba Vi National Park. (Photo: Phan Nhu).

However, according to some biologists and geographers, whether wild sunflowers are a strong invasive species in Vietnam or not is still controversial.

Origin and invasiveness of wild sunflowers

Wild sunflowers (scientific name: Tithonia diversifolia) are native to Central America. For decades, this exotic plant has flourished in Vietnam. With its brilliant yellow color and tenacious vitality, this plant has long been used by people as an ornamental plant. However, in addition to its aesthetic value, wild sunflowers also pose potential ecological and environmental risks.

According to Dr. Vu Anh Tai (researcher at the Institute of Geography, Vietnam Academy of Science and Technology), wild sunflowers are one of the most invasive plant species, especially in tropical climates. "In areas that are not strictly managed, wild sunflowers can grow strongly, overwhelm native species and change the ecological structure ," said Mr. Vu Anh Tai.

Wild sunflowers cover a corner of Ba Vi National Park in yellow. (Photo: Hanoi Life).

Previously, in June 2022, Dr. Vu Anh Tai and his colleagues published a scientific article Survey and assessment of invasive plant species in Ba Vi National Park . This is also the document cited by Mr. Dang Hoang Giang below his post. In this work, Dr. Vu Anh Tai emphasized the danger of wild sunflowers from their ability to reproduce and spread in vacant land, along roadsides or abandoned farming areas.

"In Ba Vi, wild sunflowers have invaded many areas, from paths in the National Park to farms outside. If left unchecked, this plant can have negative impacts on agricultural land and natural habitats," added Dr. Vu Anh Tai. In particular, the essential oils secreted by the plant can inhibit the germination and growth of other plant species. This creates unfavorable competition for native plants.

To control the invasion of wild sunflowers, Dr. Vu Anh Tai proposed that effective land management measures are needed, especially in newly planted forests and abandoned farmland. Research on biological methods, such as using native plants or microorganisms to control wild sunflowers, should also be prioritized.

There is no clear evidence to confirm that wild sunflowers are invasive species.

Although wild sunflowers are a highly invasive species in Ba Vi National Park, Dr. Vu Anh Tai also stated that evidence of the danger level of this plant species has not been recorded in other areas . The above opinion was also expressed by scientists at the Institute of Ecology and Biological Resources (under the Vietnam Academy of Science and Technology).

Ecologists analyze that wild sunflowers can grow well in areas with suitable climate and soil conditions, such as dry, airy soil and moderate temperatures. This species does not thrive in wetlands or sensitive ecosystems. Above all, in forests with large tree canopies that block the light, wild sunflowers cannot grow. Therefore, they only appear in roadside areas or vacant land.

A young man takes a photo with wild sunflowers in Da Lat. (Photo: Hong Tam).

'A survey of circulars of the Ministry of Natural Resources and Environment shows that wild sunflowers are not on the list of invasive alien plants in Vietnam,' said scientists from the Institute of Ecology and Biological Resources. Accordingly, in Appendix 1, Circular 35/2018/TT-BTNMT of the Ministry of Natural Resources and Environment, 6 plant species are listed as invasive plants including Water hyacinth, Five-color plant, Lao grass, Chrysanthemum, Mimosa pudica and Mai duong.

However, biologists also recommend that localities strictly manage the development of this flower to balance tourism benefits and environmental protection. Zoning wild sunflowers in specific areas not only helps maintain beautiful landscapes but also limits the risk of unwanted competition with native ecosystems. For example, in Da Lat, wild sunflowers are often planted along the roads leading from Lien Khuong airport, creating a "specialty" that attracts tourists without affecting other lands.

To ensure sustainable development, careful research on the impact of wild sunflowers on the environment is still needed. At the same time, experiences in managing alien species from other countries can also be useful lessons for Vietnam. In general, wild sunflowers are not only a symbol of natural beauty but also a typical example of harmony between humans and nature when managed properly.