A toxic tree, poison sumac (Toxicodendron vernix), rises above the Toxic Plants Garden in its striking Halloween colors. Photo: Jardin botanique de Montréal (Robert Mineau)
Here’s a bit of a Halloween theme: a garden of poisonous plants, a place where you might expect to find ghouls and goblins and miscreants of all sorts. There’s one at the Montreal Botanical Gardens, one of the world’s largest botanical gardens, with over 21,000 species.
The Toxic Plants Garden, started in 1940 under the guidance of the Garden’s first curator, Henry Teuscher, is fairly well hidden, in a little rectangular section with walls and a fence right next to the Medicinal Plants Garden … a logical choice, since so many poisonous plants are used for medicinal purposes (think of foxglove [Digitalis purpurea], source of the heart medication digitalis and the opium poppy [Papaver somniferum] from which morphine is derived). There are signs warning you the plants are poisonous.
The objective of the Toxic Plants Garden is above all to present visitors with a sample of native, naturalized or cultivated species that visitors are likely to encounter in a garden or in a natural environment. Some of these species can cause poisoning following accidental ingestion of part of the plant or eating the fruits. Others can cause skin reactions or respiratory allergies. So, don’t touch them or even breathe in their pollen! Scary!
There are some 40 poisonous plants in the Garden, including poison ivy (Toxicodendron radicans), water hemlock (Cicuta maculata) and poison sumac (Toxicodendron vernix).
Some are of historical interest. Who doesn’t know that Socrates was killed by ingesting a decoction of poison hemlock (Conium maculatum) in 399 BCE, for example? Others made waves more recently: only a few weeks ago (September 2020), there was a ricin scare when a mentally unstable Quebec woman mailed a ricin powder tainted letter to the White House in an attempt assassinate the American President Donald Trump.
Not Such a Frightening Visit
I’ve visited this garden many times and don’t find it at all lugubrious. Instead, it’s a charming little corner with some fascinating plants that you never see elsewhere. I mean, most botanical gardens would never think of growing poison ivy, yet it’s a highly attractive plant, with beautiful shiny leaves that change to spectacular fall colors.
If you’re an amateur botanist who wants to learn to identify some unusual plants, it’s also a great spot to do so. Where else will you find such a wide range of deadly, almost never grown plants in one place?
I enjoy looking at the venomous vegetation and trying to learn to recognize the individual plants, although I must admit that, to me, poison hemlock looks just like the sweet cecily (Myrrhis odorata) that I munch on all the time in my own garden. (Reminder to myself: if you find what looks like sweet Cecily in the wild, it’s best not to do a taste test.)
It’s likewise a great place to take children. They find poisonous plants fascinating and will want to know all about just how the plants can kill. Supply as many gruesome details as you can: they’ll lap it up! I further recommend pretending to bite into an imaginary leaf, then clutching your throat, choking and falling to the ground as spasms take over your limbs and your eyes finally close in simulated death. They’ll love that! Of course, even as the visit titillates the morbid side of their nature, it teaches them not to put just any plant part in their mouth. And that’s a good thing!
Other Toxic Plants Gardens
The Toxic Garden at the Montreal Botanical Garden is not alone. There are others. Here are a few I know about:
The Poison Garden at England’s Alnwick Garden seems to get a lot more press than Montreal’s one and openly promotes its deadly denizens. It’s been called “the world’s most dangerous garden”: now, that ought to attract crowds! It’s a more recent garden, dating only to 1996, yet contains some 100 poisonous plants. I haven’t seen it, but I’d love to visit.
There is also a Poison Garden at Blarney Castle in Ireland, said to contain wolfsbane, mandrake, ricin, opium and cannabis, among other toxic plants. A warning sign says children must be accompanied by adults: a wise decision. It opened in 2010, the year after I lasted visited Blarney Castle, so I haven’t see this one either. (And no, I didn’t kiss the Blarney Stone!)
The Orto Botanico di Padova (Padua Botanical Garden) in northwestern Italy, not far from Venice, which I have visited, dates back to 1545 and is best known for being the world’s oldest botanical garden that is still in its original location. It’s a UNESCO World Heritage Site and fascinating to visit, with its 16th-century buildings and dense, circular, systematic planting. It’s mostly dedicated to medicinal plants (the original purpose of botanical gardens was to bring together medicinal plants from all over the world) and plants are placed according to which of the four “humours” they were felt to belong, an old concept based on ancient Greek medicinal theory. The poisonous plants garden is off to one side.
There may be other poisonous plant gardens. If so, let me know and I’ll share that information.
🎃 Happy Halloween … but do skip those hemlock bonbons!