Plants that eat insects may be thought of as matters of science fiction, but thanks to modern films and factual information, most of us have heard of a few. The best known is a flower that lives in the swamps of the southeast; the Venus flytrap. Certainly it is a plant of interest as it uses leaf traps to grab bug meals, but it does not live even close to here.
The Northland, however, is home to several others that go for an insect meal during these summer days.
Four groups of insectivorous plants, comprising about a dozen species, live within the region. These range from the two-feet tall pitcher plants to the 4-inch butterworts, the aquatic bladderworts and the diminutive sundew.
Like most of the other plants that choose to snack on bugs, sundew live in the nutrient-poor soils of swamps and bogs, usually among sphagnum mosses. Here they open their roundish leaves and raise their tiny flowers to bloom during these hot days of July.
The entire plant with all of its many leaves and stalked florets grows in a circular rosette and is only about 2 inches in diameter. The whole plant could easily fit in the palm of your hand. Often the entire plant, especially the leaves, will appear to be a reddish color.
ADVERTISEMENT
Sundew gets its name from the circular or oval leaves. Small, usually less than one-half inch across, they reveal many spines with a sticky drop on the tip when viewed close. The liquid drop on each spine looks like syrup or honey and has a similar viscosity. Insects that pass by are lured in to these tasty-looking leaves. Those that actually land on the tiny drops are likely to stay. The insect body becomes attached to the stickiness and as expected, the bug struggles to escape. By making such movements, it stimulates the plant to respond and slowly, quite unlike the fast movements of the Venus flytrap or bladderwort, the leaf curls and closes in on itself. Exerting enough pressure and stress, the sundew leaves are able to crush the unfortunate insects and then the plant uses enzymes to digest its prey.
It appears as though the soils of the bogs and swamps are not able to provide all the needed nutrients for the sundew to flourish here, and so the plants compliment their diet by feeding on a few insects that seem to be so abundant here in the summer. No doubt, the sundew, being as tiny as it is, needs to gather very small bugs. Anyone who has gone into the swamps and bogs of July will vouch for the fact that this is a site of plenty of small insects.
Though not devouring insects, the flowers of the sundew are also of interest. The five petals are white and grow at the top of a 2- to 3-inch stalk. Only one-fourth inch wide when open, these minuscule flowers don't stay open very long. Usually when we see them, they are on a stalk that is bent in a pattern that makes the plant appear to be tying itself into a knot.
Being so small, many of us are not even going to see this animal-eating plant of the swamps. But those of us who walk or paddle into this scene may find this delightful and amazing little carnivorous plant.
Larry Weber is author of the "Backyard Almanac" and "Butterflies of the Northwoods." He lives in Carlton County and teaches natural science at Duluth's Marshall School.
