The Cucumber Tree: 

An Endangered Native Species

As harvests begin to hit farm stands in Ontario, we are inundated with delicious, fresh produce. There are strawberries, tomatoes, corn, peaches and plenty of cucumbers for those who like them. But did you know that cucumbers also grow on trees? Well, not the kind you turn into pickles or add to a salad, but Canada’s only native magnolia tree is called a Cucumber Tree.

Magnolia acuminata is a deciduous tree which grows upwards of 30 metres. It prefers moist, well-drained soils, full sun, and is usually found as a specimen tree, rather than in a stand of them. The cucumber tree is primarily located in the Eastern United States, but there are small pockets of them found in Southwestern Ontario. Sadly, the pockets in Ontario are so small that the tree is named on Ontario’s Species at Risk list, as an endangered species. As of most recent surveys, there are approximately 170-190 mature trees in Ontario, occurring in Norfolk County and the Niagara region, but due to fragmented forests, deforestation and poor habitat, these trees are threatened.

The good news is that cucumber trees don’t face extirpation any time soon, as there are plenty of them still in the US. These massive trees have large green oval leaves with smooth edges which form in simple, alternate patterns. The bark on mature trees has scaly ridges and is grayish brown. Nondescript yellowish-green flowers occur high in the tree in the spring. The subsequent fruit finally gives a clue as to the naming of the tree—the green immature fruit is shaped like a small cucumber. As it matures later in the summer, it turns dark red, until it pops open to expose scarlet seed pods dangling by delicate white threads.

While the cucumber tree is endangered, the Ontario Ministry of Natural Resources has a plan to help the cucumber tree revive. A recovery strategy is in place, which now protects the limited areas where the trees exist in Ontario. Research is underway to better understand the reproduction of the tree as well. The hope is to also increase the number of specimens, thereby ultimately moving Magnolia acuminata off the endangered list.

For those of you who are willing to help protect cucumber trees in Ontario, your task is a big one, but necessary if we want to continue to enjoy these majestic trees in Canada. Contact your local Ministry of Natural Resources and Forestry Species at Risk biologist to discuss what you can do to help move this endangered species off the list, so future generations can enjoy it as well.