Carnivorous Plants of Minnesota: A Case of Spooky Adaptation in a Fight for Survival

As Halloween approaches, people are starting to celebrate the strange, scary, and downright creepy. And what’s creepier than plants that consume living creatures for survival? 

Carnivorous plants, such as the infamous Venus flytrap, are heralded across pop culture in spooky stories, horror films, and thrillers (Little Shop of Horrors anyone?). Additionally, these plants are often featured in museums, herbariums, botanical gardens, and other places which exhibit rare, unique plants. So you might be surprised that you can find, not 1, but 4 different genus of carnivorous plants occurring naturally in Minnesota. But what exactly does carnivorous mean? Certainly there aren’t any areas of Minnesota where you are at risk of being attacked and eaten by a giant flytrap….right? 

Well, we can’t say for sure, but you’re certainly safe from the carnivorous plants we do know about. These freaky plants are “insectivores,” or insect digesting plants. Now digesting insects probably sounds disgusting, which might beg the question why bother at all? Don’t plants get their food from the sun through photosynthesis? The answer is yes!—plants do get food from the sun; but plants need many other nutrients to survive. 

The carnivorous plants native to Minnesota all have one thing in common (other than questionable cuisine choices)—they all grow in nutrient-poor habitats. These plants are all adapted to wetland ecosystems such as fens and bogs where the saturated soil conditions result in nutrient-poor, oxygen-deficient growing conditions. With such harsh conditions, it may be surprising that plant life thrives at all. That’s where the freaky, creepy, Halloween-caper worthy plant characteristics come in. Plants at home in these environments produce unique traits and adaptations to deal with the less-than-ideal conditions. Insect-digesting is one of these adaptations. Carnivorous plants trap and digest insects for the nutrients inside them. It may be a bad break for the insect; but these buggy victims provide important nutrients, such as nitrogen, that these plants need to survive and maintain the plant community that supports the entirety of these ecosystems. Northern Minnesota is full of peatlands such as those where carnivorous plants thrive, so it’s unsurprising that we have as many different species of insect-consuming plants as we do.

Now that we know where and why carnivorous plants exist, let’s take a greater in-depth look at those that can be found throughout Minnesota. There are a number of different species of carnivorous plants, split into four genus: pitcher plants (Sarracenia), Sundews (Drosera), butterwort (Pinguicula), and bladderworts (Utricularia).

Purple pitcher plant

Insects that fall into the ensnaring cup of the Purple pitcher plant (Sarracenia purpurea) face a slow doom. The center of the plant is shaped like a pitcher, and functions like a pit trap. The inside of the pitcher is covered in stiff hairs that point downward and prevent the insect from being able to crawl back out again. Since the interior of the pitcher is often also full of rainwater, the insects eventually drown. Digestive enzymes then set to work releasing nutrients from the insect into the plant for consumption. One of the most common carnivorous plants in Minnesota, pitcher plants (you also may hear them called cup plants) can be found in many of the peat bogs such as Big Bog in northern part of the state. 

Sundews

You might miss the unassuming Sundew plant (Drosera spp.), as these species tend to grow low to the ground. However, stopping to check out these unique plants is worth it. Their alien-like structure includes tentacle-like, long, sticky leaves that stick out from the central body like colorful spikes. These spikes are the key to this plant’s dangerous trap. Small insects get stuck to the sticky leaves, which then curl inward, trapping the helpless insect further and drawing it into the digestive center of the plant. There are multiple Sundew plants native to Minnesota, but two in particular, Drosera linearis and Drosera anglica, are of special concern. These species are limited to very specific, high-quality habitats that have suffered minimal disturbance. Called fens or patterned fens, these wetlands take centuries to slowly accumulate the layers of peat characteristic of them. They are extremely vulnerable to disturbance, and once destroyed, are not possible to restore in our lifetimes. Both D. linearis and D. anglica require these unique but disappearing habitats to survive, and both were listed as special concern species in Minnesota in 1996. Thankfully, the value and vulnerability of these ecosystems were recognized, and many acres were reserved in Scientific and Natural Areas protected by the state. Protection efforts will need to continue, however, if we hope to prevent these unique carnivores from becoming true ghosts in the future.

Butterwort

Common butterwort (Pinguicula vulgaris) has a bit of a deceptive name; it is actually quite rare in Minnesota. A species that is more common at higher latitudes, butterwort has little viable habitat in Minnesota. It requires high-quality shoreline habitats along Lake Superior, and currently only a few colonies of butterwort exist. The species was listed as a state special concern species in 1984. Like the other carnivorous plants of the state, butterworts digest insects as a source of nutrients. Butterworts exhibit a similar trapping system to the more common Sundews, with sticky hairs lining the upper side of their leaves. These hairs ensnare and entangle insects, which only become more trapped as they try to escape. Secondary glands along the leaves secrete digestive enzymes which pool around the insects, eventually leading to their demise and consumption.

Bladderworts

Bladderworts (Utricularia spp.) are underwater hunters among the carnivorous species. The submerged stems of these plants are covered in bladder-like structures designed to be suction-traps for passing aquatic insects. Since they are submerged in water, there is a negative pressure within the bladders. This means that when the bladders open, nearby water is sucked inside, along with anything swimming in that water. Tiny hairs lining the bladder trigger at the slightest touch of passing invertebrates. When triggered, the bladderwort opens and instantly the unlucky invertebrate is sucked in like a vacuum and trapped as the bladder closes once more. Trapped invertebrates quickly become nutrients for the plant. Like Sundews, there are multiple types of bladderworts found in Minnesota, but a few rare ones are worth mentioning. Utricularia geminiscapa is an elusive phantom among plants, not being discovered in the state until 2004. These plants make their homes in quality, natural pools found in fens and bogs, and suspend in the water column rather than floating on the surface or rooting in the soil. Such habitats are hard to come by, and as such, there are very few individuals of this species known within the state. U. geminiscapa was designated as a threatened species in 2013. Another phantom among Minnesota bladderworts is Utricularia purpurea. This species is one of the rarest aquatic plants in Minnesota, requiring high water quality to survive. Unfortunately, most lakes in Minnesota are trending toward ‘impairment’ status for water pollution, making the future of this species uncertain. U. purpurea received endangered species status in the state in 2013.

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Exploring carnivorous plants is a fun Halloween theme, but they do point to an important aspect of restoration and land stewardship—the need to protect our dwindling wetland resources. The kinds of habitats where these special plants grow have historically been disregarded as waste areas or useless habitats. Rarely have swamps, fens, and bogs received the same glowing accolades as their regal forest or prairie brothers; but these seemingly dreary landscapes are the only homes many plant and animal species have to survive. Millions of acres of these peatlands have already been lost to human activities such as draining for development and peat mining. Restoration of these landscapes is difficult due to the length of time required for peat to accumulate, so conservation and preservation is extremely important. While creating a good backdrop for any scary story, bogs, and the carnivorous plants that live in them, are a key part of Minnesota history and ecology. So as you’re celebrating the spooky this October, don’t forget to appreciate value of our natural, spooky landscapes and the quiet insect hunters that grow there.