Tumba Rabu - The Tree that Pops up Everywhere
(Published in the newspaper Amigoe on the 26th of August 2026)
Tumba Rabu
Anyone who regularly drives around Curaçao has probably seen it thousands of times without thinking about it. Along roads, on vacant lots, around construction sites and on pieces of land that were once cleared, there is a tree with fine green leaves and long, flat brown pods. Often he is not alone. Where one specimen grows, there are soon dozens.
This is Tumba Rabu, with the scientific name Leucaena leucocephala. The species is native to Mexico and the northern part of Central America. So he does not naturally belong on Curaçao. In the meantime, Tumba Rabu has become so common that it is hard to imagine that there was a time when this tree did not grow here. And he still seems to be gaining ground.
Tumba Rabu with flowers and pods (Photo: Carmabi)
A world traveler
Tumba Rabu is certainly not a typical Curaçao problem. Leucaena leucocephala has been spread by humans over a large part of the tropical world. That happened for a reason. It is a very useful tree.
It grows quickly, can withstand drought and poor soil and the leaves contain a lot of protein. That is why Leucaena was planted in many countries as animal feed. The wood could be used as firewood, and the tree was also planted to prevent erosion and improve the soil. The latter is possible because Leucaena belongs to the legume family. Like many other plants in this family, it lives together with bacteria that can fix nitrogen from the air. This allows it to grow on soil where other plants have a harder time. An ideal tree. Until it starts to grow in places where you don't want it.
Its native range is in Mexico and the northern part of Central America. However, Leucaena has become invasive in many countries today. Leucaena leucocephala is considered one of the 100 most invasive species by the IUCN Species Survival Commission's Invasive Species Specialist Group. Below is a map of the distribution of Leucaena leucocephala with the original distribution area in green and the countries where it was introduced in purple.
Map distribution Leucaena leucocephala (Photo: RBG Kew POWO)
Long on Curaçao
When exactly Tumba Rabu was brought to Curaçao and by whom, is not clear. We do know that the plant was cultivated here more than a century ago. The Dutch botanist Isaac Boldingh mentioned Leucaena leucocephala as a cultivated plant on the Dutch Caribbean islands in 1913. It then escaped from gardens, yards or plantations and became part of the wild vegetation. It even occurs in the Christoffel Park.
Give him a bare piece of land
One of the most important features of Tumba Rabu is that it makes excellent use of disturbance. Think of a site that is being cleaned for housing. A piece of land that is shoved bare with a bulldozer. A verge that is mowed regularly. An abandoned construction site. Or land where the original vegetation has disappeared for another reason. That's where Tumba Rabu gets its chance.
A factory full of seeds
Tumba Rabu has another big advantage. He makes a lot of seeds. The flowers of Tumba Rabu are close together in round, white to creamy white heads. Such a flower head usually has a diameter of about 1.5–3 cm and stands on a long flower stem. The long thin stamens that protrude from the flower head give the flower head a fluffy appearance. After flowering, the well-known flat pods appear. Each pod contains several hard seeds.
After flowering, the flat pods appear (Photo: John de Freitas)
A mature tree can produce hundreds of pods and thousands of seeds per year. Under favourable conditions, the plant can also produce flowers and seeds within a year of germination.
Pods of Leucaena leucocephala (Photo: RBG Kew POWO)
The seeds can remain in the soil for a long time. This creates a kind of storage room underground. If you cut away the mature trees, it does not automatically mean that Tumba Rabu has disappeared. As soon as the conditions are right, new seedlings can emerge. There is something else. If you cut off a Tumba Rabu, it can sprout again. Removing the trunk alone is therefore often insufficient. All this makes the species a particularly successful intruder: fast growth, many seeds, a long-term seed supply in the soil and the ability to resprout after damage.
Why is it called Tumba Rabu?
The Papiamento name is at least as interesting as the plant itself. Rabu means tail. Tumba can mean to topple, but it can also be used figuratively for something that makes someone or something deteriorate physically. A possible explanation for the name Tumba Rabu has to do with a special substance in the plant: mimosine. Leucaena contains mimosine in leaves and seeds, among other things. This substance can be toxic to animals when they eat large amounts of the plant.
This can cause problems, especially in animals that cannot process Leucaena properly. In horses, the effect is striking. Scientific research on horses that ate a lot of Leucaena leucocephala describes decreased appetite, weight loss and lethargy. But the most visible symptom was hair loss. And it was precisely the mane and tail that were affected.
This suddenly makes the Curaçao name Tumba Rabu very visual: a plant that affects or brings down the rabu, the tail, as it were. Whether the name actually originated historically for this reason is difficult to prove with certainty. But biologically, the explanation is quite possible. In any case, the link between eating Leucaena and hair loss from the mane and tail in horses is not a folk tale. It has been scientifically proven.
Ruminants, such as goats and cattle, can deal better with Leucaena under certain conditions, partly thanks to microorganisms in their rumen that can break down harmful substances. This does not mean that unlimited food is automatically safe for every ruminant animal.
When one species takes over the space
But Tumba Rabu is not only a problem for animals. The main nature problem is that the tree can form very dense vegetation. On a disturbed site, hundreds of young plants can grow close together. They grow upwards quickly, taking up light and space that would otherwise be available to other plants. Research on islands where Leucaena has become highly invasive shows that areas with a lot of Leucaena can contain significantly fewer native tree species than areas without the invader.
There are also indications that mimosin and other substances from Leucaena can inhibit the growth of other plants. Scientists are still investigating exactly how important that effect is under natural conditions. It could be an extra advantage with which Leucaena keeps its competitors at bay. In any case, the result is clearly visible. In suitable places, a mixed vegetation can slowly change into an almost continuous field of Tumba Rabu.
A problem that we help grow ourselves
This makes Tumba Rabu different from some other invasive plants. The tree does not have to go deep into the pristine mondi to be successful. We are constantly creating new living space for him. Every road, construction site and every cleared site can be a new beginning.
In doing so, this inconspicuous tree tells a larger story about invasive species. An invasive species does not have to be spectacular. He doesn't have to have huge thorns or suffocate trees. Sometimes his greatest strength is simply that he takes advantage of the opportunities we give him faster than the rest.
Tumba Rabu has been on Curaçao for more than a hundred years. Yet his rise does not seem to be over yet. If you pay attention, you will suddenly see it everywhere: along roads, between houses and especially in places where the original vegetation has disappeared. Perhaps that is the most important characteristic of Tumba Rabu. Where we disturb the mondi, he is ready to take over the vacant space.