Saving the world's largest flowers in the Philippines

RAFFLESIA is a parasitic plant that spends most of its life cycle within its host, a tropical vine, emerging only to bloom. Its flowers are the largest in the world, spanning up to a metre. Despite this, little is known about its life cycle, and it is almost impossible to grow.

Half of the Rafflesia species known to science were described in the past two decades, yet most have since come close to extinction. This is a plant in peril. On a recent trip in the Philippines, I saw a population decimated to make way for crops. As is often the case, a smallholder farmer was responsible – somebody just trying to make ends meet.

What is the solution? Protecting habitats is the best safeguard. But this only works if we know where Rafflesia occurs in the first place. Often, we don’t. Local community action groups are crucial in this respect to monitor populations.

Beyond in-habitat conservation, most plants can be protected in seed banks or botanic gardens. But Rafflesia is an intractable parasite. The only botanic garden to have cultivated it successfully is in Bogor, Indonesia, where Rafflesia-infected vines are grafted onto new, uninfected rootstocks.

In 2022, my colleagues Pastor Malabrigo Jr and Adriane Tobias at the University of the Philippines Los Baños and I went to Bogor to learn how to grow the ungrowable. Back in the Philippines, we attempted the country’s first ever Rafflesia propagation in a protected forest reserve. If our R. panchoana graft is successful, we will have created a template for propagating Rafflesia species on the brink of extinction in the Philippines.

Chris Thorogood is deputy director of the University of Oxford Botanic Garden and author of Pathless Forest