Tale of cat’s claw vine

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By Sayuni Masakorala

Breathtaking as it may seem as a springtime attraction, cat’s claw vine (Dolichandra unguis-cati) is a creeper which can present itself as a potential invasive. Commonly visible in the vicinity of Peradeniya in yellow blooms, it’s a prolific fast-growing creeper which is often popularised for its beauty. Unbeknownst to the public it is a creeper of diabolic nature which possesses a dark side, as it could very well act as an invasive disrupting the ecological balance.

The exotic beauty: ‘breathtaking yellow blooms’

Speaking with us at Ceylon Today, Research Professor at National Institute of Fundamental Science and former Director General, National Botanical Gardens in Kandy Siril Wijesundara, said, “During the British period, cat’s claw vine was introduced through botanical gardens with the objective of studying flora of Sri Lanka and as a part of plantation economies. The cat’s claw vine was first introduced from Brazil to the 

Sri Lanka Botanical Gardens in 1850.  It is a creeper which ‘climbs trees’ using hook like structures.  It grows very fast and can be grown easily in the Wet Zone. It originally belonged to the genus ‘begonia’ and was later recognised in relation to the genus ‘dolichandra’.  This creeper is known by several scientific names such as bigonia unguis carti, macfadyena unguis carti and the latest being dolichandra unguis carti. It ‘flowers’ in late February in large numbers which makes it an attractive sight as it looks like a layer of yellow carpet.”

Invasive alien species

In relation to the invasive nature of the creeper, he said “The cat’s claw vine has been considered as an invasive species in many countries and has been placed in the list of Invasive Alien Species (IAS) prepared by the Invasive Species Specialist Group (ISSG).  However, it is still not considered an invasive species in Sri Lanka yet. This is due to the concentration of these flowers at present being restricted to a few areas in distribution, where the largest concentration of these flowers can be seen in the vicinity of the University of Peradeniya.  It remains a threat as a potential invasive with it being widely distributed as an ornamental plant due to its beauty being glorified through media outlets.” Further he said, as an IAS it could cover entire canopies, affect photosynthesis of the host plant, and even affect vegetation around it.

We at Ceylon Today, spoke to Senior Environmental Lawyer Dr. Jagath Gunawardana about the adverse impacts of the cat’s claw vine being a potential invasive. He said, “`The cat’s claw vine is an exotic species that people look forward to in its flowering season. This is evident from the numerous social media posts and poems which are circulated yearly surrounding the beauty of this creeper. However, this fast-growing vine poses many problems to host trees. The mass of vines add a considerable weight onto branches of trees. In turn these branches and even small trees have collapsed under the weight of the vines. The smaller vines cover the branches which makes the branches defoliate and eventually die. There are instances where a whole tree had died after being covered and smothered by the cat’s claw vine.  Even taller trees are not safe from this vine as this creeper can easily reach the canopy of most and thereafter spread over, smothering the canopy. Since, the vine produces large numbers of leaves, the leaves shed forming a thick mat of fallen leaves that can prevent the germination of seeds and cover the smaller plants that grow on the floor.”

Adequate safeguards on ornamental usage

He also added that, “As the creeper possesses invasive characteristics it is best not to use it as an ornamental plant. If it is to be used as an ornamental plant, adequate safeguards should be followed. The plant is visibly used as an ornamental plant in status quo. I have recorded a few sightings in areas near the Dehiwala Zoo, Kurunegala and Colombo. Due to the distinct claw like structures, it is easy to both identify them and propagate them.  With the increased urbanisation of this plant, it is pertinent to take necessary precautions. The preferrable mode of ensuring that remnants of trimmings don’t escape and become invasives, is to burn all the pieces which were trimmed. Further, accumulation of remnants of trimmings in garbage dumps should be prevented as it could also act as a mode of propagating these vines.” On a final note, he mentioned that as beautiful as it may seem, it is yet another exotic ornamental plant in Sri Lanka with the potential of becoming an IAS in the future if adequate safeguards are not implemented. Therefore, the best action with regard to these creepers would be to take pre-emptive action by assessing its risk levels through risk assessments and as the public to be silent observers in preventing a potential risk creating imbalance in ecosystems.