Houseplants Travelog

The Highs and Lows of the Biodome’s Rainforest

Recently, I went to the Montreal’s Biodome. It’s funny, because most people go there to see the animals, but for me, a laidback gardener looking for things to write about, it was the plants that interested me. What I learned about plants, especially those in the tropical jungle, is really funny, amazing… and even ironic.

If you think you’re the only ones who have to repot, stake, prune and manage pests, think again: the folks at the Biodome (and certainly at many other zoological institutions around the world) have to deal with the same problems… but in a life-size version!

If you don’t know the Biodome, it is one of the 5 Space for Life museums presenting natural ecosystems in a vast indoor space. Visitors follow the pathway and can admire wildreness all around them, both plant and animal (even mineral). Five ecosystems are presented: the tropical forest, the Laurentian forest, the Gulf of St. Lawrence and the Arctic and Antarctic poles.

Two Laidback Gardeners in the Forest

Two of them? Well, yes! Another blog contributor, Francis Cardinal, works at the Biodome as an educator and scientific designer. During my visit, I took the opportunity to ask him questions and learn more about the plant life behind this incredible museum and I was not disappointed.

I would like to quote my source: if you work at the Biodome and you realize that I said something wrong… Well, it’s Francis’ fault!

Space Constraints From Below

How is your banana tree? Do you have to repot it? Come on, surely it can manage otherwise, after all, the gigantic tropical trees that touch the ceiling at the Biodome only have their feet, or rather their roots, in a single meter (3 feet) of soil at most, sometimes less.

Wait, what? One meter? For a tree (Sterculia mexicana) of 18 meters (60 feet) high?

That’s right! That’s incredible, isn’t it?

Well, I don’t want to tell you how much compost, fertilizer, manure and other things are needed. Some animals probably contribute naturally to this, but it is far from enough.

It is also necessary to make sure that the products used are not toxic for the fauna living in this habitat. We must forget about using heavy machinery to spread all this: the risk of damaging the plants is far too great. The rainforest is dense!

Space Constraints From Above

Prune to clear pathways, prevent plants from breaking through the ceiling, and provide good visibility for visitors. Chop chop!

That’s a lot of pruning to do, but also a lot of branches to get rid of.

“It’s not so bad, Audrey! I need to prune my hedges once a year, after that it’s maintenance only…”

Are you familiar with the balsa tree (Ochroma pyramidale)?

In six months, this plant goes from a small shoot to a 30 centimeters (1 foot) diameter trunk and reaches a spectacular height of 4 to 5 meters. Yep, nature grows fast when there is no winter (dormancy) and the weather is always warm and beautiful!

Space Constraints on the Sides

Yes, there are many space constraints when you put a forest indoors! In a “real” jungle, you can’t see very far and you don’t know where to put your feet either. Dead trees are used to support climbing vines and the piles of leaves on the ground are never innocent: they hide holes, snakes, rocks or more plants.

If we transpose this to the Biodome, good luck following the trail! Would you see that, you, having to step over fallen trees, push back monstera leaves to see a few steps ahead? And then BAM! A parrot biting your nose!

All this to say that there is a great need for staking at the Biodome. Not little bamboo stalks, we’re talking about steel cables that prevent trees from falling or growing sideways. Imagine if a tree grew at an angle and ended up falling: the material breakage could be catastrophic!

But fear not, the stakes are very subtle. In fact, without Francis, I probably wouldn’t have even seen them.

You can even see in this photo the different cable marks as the tree has grown!


« Use some insecticidal soap!”

Haha I’d like to see horticulturists scrub every leaf with insecticidal soap! Lots of resignation letters ahead!

In fact, since this is a self-sustaining ecosystem, unless there is a huge infestation, nothing is done! I know, it’s surprising, but a natural balance is established. In nature, there are all kinds of bugs and they are part of the great cycle of life: the monkey eats insects, its excrements feed the plants, these produce fruits which in turn feed a panoply of species. This is how life works!

At the Biodome, everything is controlled by the clock. Pests are tolerated as long as they don’t cause too much damage. I observed ants, flies and even a few mice!

Francis told me that in order to reduce the amount of certain pests – the Australian cockroaches – cane toads were introduced as predators. This is the same species that has been causing incredible damage in Australia since its introduction.

Are all their plants perfect? No, far from it, but in nature, they are not either! It’s normal to have brown, torn or bird droppings on the leaves!

Temperamental Species

“My plant used to look great, but I moved it to another location and it’s losing all its leaves.”

Plants have specific needs and usually settle down on their own in places that suit them in nature. In the indoor rainforest we’re talking about, conditions are ideal for most plants…but not all.

Careful choices must be made when introducing a new plant. A peace lily is “not killable”! What a great choice to put near the door that is constantly opening and closing! But the cocoa tree is having a hard time of it…

Peace Lily

In fact, Francis confided in me that during the renovations in 2018-2020, the cocoa tree produced… a pod! It must be said that since the place was closed to the public, the temperature and humidity may have been much more stable and comfortable for this tree.

(Or maybe it was bored and tried to lure people back by dangling the possibility of eating chocolate…)

There’s a great green wall too. I couldn’t help but think of Larry’s. Having followed his ups and downs with this creation, I felt challenged. Imagine the ladder needed to get access to these plants!

Some Real… and a Little Fake

Although the Biodome has done a remarkable job of making its habitats as realistic as possible, there are still many constraints to manage with an indoor forest. Think of the equipment to balance temperature and humidity, lighting, drains, ventilation… It’s hard to give the illusion of being in a forest with wires or pipes hanging everywhere!

That’s why some trees or rock walls are fake. They actually hide everything that allows to maintain the right weather (among other things). I reassure you, they are well integrated into the scenery and you almost can’t see them.

Well, when a misting jet comes out of a tree, we have our doubts, anyway!

These unnatural elements are totally in harmony with the surrounding nature and they are a very good logistical choice. I’d love to hide my electrical wires with large rocks, but that might be weird (and expensive) in a house…

Go back through the photos and try to spot anything unnatural!

By the way, here’s a picture of a “real thing” that I thought was impossible: a MAGNIFICENT aloe vera growing in a tree! Why impossible? Because I, for all my love, am a serial killer of aloes…

Conclusion: Les Horticulteurs Du Biodôme Sont Loin D’être Des Paresseux…

… but they work in the same habitat as four real sloths, so I guess it’s even! It’s interesting to see that, despite the size of the project, the problems are the same as those we encounter in our homes. My hat goes off to those who are working on it and finding solutions to these “big” problems!

I learned a lot during this day thanks to Francis, but I also discussed with several very interesting educators. I invite you to ask them your questions the next time you visit. They always have something interesting to say.

By the way, and this is not a myth, I did see a sloth, a REAL one, in the Biodome forest. Keep looking for it on your next visit… if you are not too slothful!

Audrey Martel is a biologist who graduated from the University of Montreal. After more than ten years in the field of scientific animation, notably for Parks Canada and the Granby Zoo, she joined Nature Conservancy of Canada to take up new challenges in scientific writing. She then moved into marketing and joined Leo Studio. Full of life and always up for a giggle, or the discovery of a new edible plant, she never abandoned her love for nature and writes articles for both Nature sauvage and the Laidback Gardener.

1 comment on “The Highs and Lows of the Biodome’s Rainforest

  1. Looks like an incredible place to visit. Thanks for the inside tour.

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