Utricularia vulgaris

Utricularia vulgaris (Common bladderwort) is a variety of aquatic carnivorous plant distinctive for its multiple underwater “bladders,” which it uses to capture its prey. Common bladderwort is just one of around 220 species of bladderwort that are found in fresh water and wet soil around the world. 

Unlike some of bladderworts’ more famous carnivorous plant cousins, Utricularia vulgaris hunts below the surface of the water so its activity is more difficult to observe. Even if you are able to see their bladders clearly, their prey is generally too small to be visible without magnification. This is not the best choice for people looking to observe the excitement of watching a carnivorous plant devouring an animal. Regardless, bladderworts have beautiful flowers and attractive foliage, and their unique way of capturing small invertebrates to consume is fascinating and worthy of more attention. 

Common bladderwort does not get all of its nutrients from eating animals. It has a root system that provides some nutrients, but it also supplements its diet by consuming tiny aquatic organisms such as copepods and nematodes. The mechanism it uses to catch prey starts with the small bladders which give the plant its name. The opening of each little pouch is surrounded by sensitive trigger hairs that cause the bladder to quickly open when they come in contact with a passing organism. The rapid speed of the trap opening causes the surrounding water and any creatures in that water to flow into the bladder, where they are then trapped. 

Utricularia vulgaris is one of the fastest-moving plants in the world, as their bladders are able to capture prey in less than a millisecond. Once inside, the digestive juices break down the ensnared organisms to make their nutrients available for the bladderwort to use. 

Remarkably, the bladderwort’s bladders do double-duty beyond simply catching prey. They also serve to keep the plant buoyant by filling with air while the plant is in its active blooming season. Then, when it is time for the bladderwort to go dormant in the winter, the bladders fill with water so the plant can sink below the water’s surface. 

Because of its relatively unremarkable appearance, it can be difficult to identify Utricularia vulgaris in the wild even though it is common in many places. The most distinctive feature is the Common bladderwort’s yellow flowers that resemble snapdragons or small orchid blooms, which emerge from stems that are generally reddish-green. Checking below the surface of the water, it is easy to see the many small bladders clinging onto the root system.  

Utricularia vulgaris makes a great addition to a pond or other water feature. Its flowers and foliage are attractive, and the bladders help to reduce the number of mosquito larvae present in the water. However, depending on conditions, bladderwort can be somewhat aggressive and crowd out other plants. For that reason, it is best to grow it in locations where it is already an established and non-invasive species.