Insect-Trapping Aquatic Plants

Bladderworts

• Bladderworts use small bladderlike traps to capture insects, small invertebrates and tiny fish. The bladderwort's trap works something like a suction bulb. When tiny hairlike projections around the opening of the bladder sense an insect or other creature passing by, they cause the trap to inflate, sucking in water along with their prey, and trapping it inside. Bladderworts live in open water like bog lakes, and can be found throughout the northern hemisphere. They don't have true leaves. Instead, highly branched, leaflike stems can be found floating or submerged underwater. Occasionally, this plant will attach itself loosely to the sediment. Bladderworts have yellow, snapdragonlike flowers with faint purple-brown stripes.

Growing Bladderworts

• Grow aquatic bladderworts outdoors in ponds or fountains. Grow indoors in large aquariums without any fish, because fish will eat your plants. Add peat moss to the bottom of your pond or aquarium to increase the acidity of the water. Don't expose bladderworts to fertilizer or gardening soil. Bladderworts like partial to full sun and a lot of water. If you're growing them outside, make sure the bottom of the fountain or pond is below the frost line because plants sink to the bottom of the pond during their period of winter dormancy. Bladderworts don't produce enough oxygen from photosynthesis and need additional dissolved oxygen in the water where they grow. Aerate their water to provide additional oxygen.

Waterwheels

• Waterwheel plants are closely related to Venus flytraps, using snap-traps to capture insects and other small prey. These rootless plants float just below the surface of the water. The leaves grow in whorls and end in clamlike traps that snap shut when the long, sensitive hairs are stimulated and triggered by passing prey. Traps close in 1/4 to 1/2 second and reopen in 10 to 20 hours if no prey is captured. Waterwheel plants have small white flowers and grow to be about 6 inches long. They can be found in Australia, Africa, Europe and India and are a threatened species in some areas due to high levels of pollution, illegal collection and destruction of natural habitat.

Growing Waterwheels

• Waterwheels are difficult to grow. They don't like algae and do better in acidic water. Grow them in an outdoor bog pool or in a large tank that's at least 30 gallons in size. Plants require a period of dormancy in the winter so, if you're growing them outside, ensure that the pool bottom is about 18 to 24 inches below the frost line. Add 1 inch of peat moss and leaf litter to the water at least one week before planting your waterwheels, to limit the growth of algae and allow tannins to be released into the water. Include companion plants like water lilies, cattail and pickerel weed to help produce food for the waterwheels and reduce the growth of algae. Waterwheels prefer warm, sunny conditions. Since they trap their own food, it's not necessary to feed them.