Critters of North Idaho: Sundew

Lurking in the marches, fens and bogs of the Idaho Panhandle is a voracious predator lying in wait for its next meal. What is this predator? It’s not a mammal. It’s not a bird. It’s not reptile, amphibian, fish, or an invertebrate. In fact, it’s not even an animal at all. It’s a plant — a carnivorous plant! Today we’re going to meet the sundew!

Sundews are any plant belonging to the genus Drosera, of which there are almost 200 species found across every continent in the world except Antarctica. Two species are native to northern Idaho: the roundleaf sundew (Drosera rotundifolia), and the English sundew (Drosera anglica). The English sundew is believed to have originated as a hybrid between the roundleaf sundew and the slenderleaf sundew (which is not native to Idaho), later becoming its own unique species.

If you were to walk by these plants, you probably wouldn’t even notice them. Sundews, after all, are just little, unassuming-looking plants, growing no more than 10 inches tall. They even sprout little white flowers in the summertime.

But don’t be fooled by their harmless appearance. Their leaves grow in a rosette outward from the main plant and are covered in tiny, red hair-like structures that each secrete a sticky droplet on the end. Sundews produce a sweet smell that attracts flies, mosquitoes, bees, wasps, beetles and other insects hoping for a meal.

When they land on the sundew’s leaves, they find out all too late that they are stuck in the plant’s sticky secretions. Sundews don’t snap shut once they’ve got something, which is a behavior you may recognize with another carnivorous plant: the Venus flytrap.

Instead, special sensors alert the plant to let it know that dinner has been caught, and then the leaf slowly folds up over the struggling insect. Next, the leaf secretes special enzymes onto its prey that digest it, turning it into an absorbable mush which the plant consumes. Not a particularly nice way to go!

Sundews are only some of the 600 or so species of carnivorous plants in the world. These plants do not come from a common ancestor, meaning many of them have independently chosen such a lifestyle. But what factors would drive these plants to eat insects?

The wetland habitats that sundews and other carnivorous plants call home are very acidic, which discourages the growth of fungi and bacteria that otherwise fill the soil with nitrogen and other nutrients. Without those nutrients, these plants have turned to alternative sources of food: insects.

In addition to providing us with free pest control, the enzymes sundew leaves secrete can also be used to curdle milk and contain antibiotic and anti-inflammatory properties.

For this reason, some Swedish people use these plants to make cheese. If you have any desires to try this for yourself, it is NOT recommended that you remove these plants from the wild. Many species and populations of sundews are endangered due to habitat encroachment. But that doesn’t mean you can’t make these little carnivorous greens a part of your life. They, along with pitcher plants, Venus flytraps and others can be found at your local plant nursery!

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